diff --git a/.gitattributes b/.gitattributes
index 91df4f0eb18..b08c45648d9 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -5,3 +5,4 @@ tests/source/configs/enum_discrim_align_threshold/40.rs -text
 tests/target/issue-3494/crlf.rs -text
 tests/target/comment_crlf_newline.rs -text
 tests/target/configs/enum_discrim_align_threshold/40.rs -text
+tests/editorconfig/target/eol-crlf/main.rs -text
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6b6d9a3b8dc..938a137a617 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,38 @@
 
 ## [Unreleased]
 
+### Added
+- rustfmt now has unstable support for [.editorconfig](https://editorconfig.org/), enabled with `--unstable-features --use-editorconfig`.
+  The following `.editorconfig` options are respected when applied to Rust source files:
+
+  ```ini
+  [*.rs]
+  # These three options cannot be modified, as they do not have corresponding rustfmt options.
+  # If they are present at all, they are required to take on certain values:
+  # Required to be utf-8 or utf-8-bom.
+  charset = utf-8
+  # Required to be true.
+  trim_trailing_whitespace = true
+  # Required to be true.
+  insert_final_newline = true
+
+  # These options correspond to existing stable rustfmt options.
+  # Corresponds to hard_tabs (spaces => false, tabs => true).
+  indent_style = spaces
+  # Corresponds to tab_spaces.
+  indent_size = 3
+  # Alternatively, this combination sets tab_spaces via tab_width:
+  indent_size = tab
+  tab_width = 3
+  # Corresponds to newline_style (lf => "unix", crlf => "windows", cr is unsupported).
+  newline_style = lf
+  # Corresponds to max_width.
+  max_line_len = 100
+  ```
+
+  Note that only the configuration for the entry point (e.g. `main.rs`, `lib.rs`, or integration tests) is respected, but not for child modules.
+  Use a `[*.rs]` section in your .editorconfig to avoid surprises.
+  There is no dedicated support in `cargo-fmt`; use `cargo fmt -- --unstable-features --use-editorconfig` to pass the option through to rustfmt.
 
 ## [1.10.0] 2026-07-21
 
diff --git a/Cargo.lock b/Cargo.lock
index 9ba1ded57c8..45bc8d871e0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -251,6 +251,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "ec4rs"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b31a881d38439026e3d5dd938ab20328d36e23caca8fd5981c42e4b677f5842"
+
 [[package]]
 name = "either"
 version = "1.6.1"
@@ -583,6 +589,7 @@ dependencies = [
  "clap-cargo",
  "diff",
  "dirs",
+ "ec4rs",
  "getopts",
  "ignore",
  "insta",
diff --git a/Cargo.toml b/Cargo.toml
index 7e4d2e60565..2cca17913d9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -42,6 +42,7 @@ clap = { version = "4.4.2", features = ["derive"] }
 clap-cargo = "0.18.3"
 diff = "0.1"
 dirs = "6.0"
+ec4rs = "1.2"
 getopts = "0.2"
 ignore = "0.4"
 itertools = "0.15"
diff --git a/src/bin/main.rs b/src/bin/main.rs
index 05a22324d0f..9e6a3771b62 100644
--- a/src/bin/main.rs
+++ b/src/bin/main.rs
@@ -192,6 +192,11 @@ fn make_opts() -> Options {
             "skip-children",
             "Don't reformat child modules (unstable).",
         );
+        opts.optflag(
+            "",
+            "use-editorconfig",
+            "Respect .editorconfig settings for Rust source files.",
+        );
     }
 
     opts.optflag("v", "verbose", "Print verbose output");
@@ -255,7 +260,7 @@ fn execute(opts: &Options) -> Result<i32> {
             let file = PathBuf::from(path);
             let file = file.canonicalize().unwrap_or(file);
 
-            let (config, _) = load_config(Some(file.parent().unwrap()), Some(options))?;
+            let (config, _) = load_config(Some(&file), Some(options))?;
             let toml = config.all_options().to_toml()?;
             io::stdout().write_all(toml.as_bytes())?;
 
@@ -349,8 +354,7 @@ fn format(
         } else {
             // Check the file directory if the config-path could not be read or not provided
             if config_path.is_none() {
-                let (local_config, config_path) =
-                    load_config(Some(file.parent().unwrap()), Some(options.clone()))?;
+                let (local_config, config_path) = load_config(Some(&file), Some(options.clone()))?;
                 if local_config.verbose() == Verbosity::Verbose {
                     if let Some(path) = config_path {
                         println!(
@@ -531,6 +535,7 @@ struct GetOptsOptions {
     quiet: bool,
     verbose: bool,
     config_path: Option<PathBuf>,
+    use_editorconfig: bool,
     inline_config: HashMap<String, String>,
     emit_mode: Option<EmitMode>,
     backup: bool,
@@ -568,6 +573,9 @@ impl GetOptsOptions {
                 if let Some(ref file_lines) = matches.opt_str("file-lines") {
                     options.file_lines = file_lines.parse()?;
                 }
+                if matches.opt_present("use-editorconfig") {
+                    options.use_editorconfig = true;
+                }
             } else {
                 let mut unstable_options = vec![];
                 if matches.opt_present("skip-children") {
@@ -579,6 +587,9 @@ impl GetOptsOptions {
                 if matches.opt_present("file-lines") {
                     unstable_options.push("`--file-lines`");
                 }
+                if matches.opt_present("use-editorconfig") {
+                    unstable_options.push("`--use-editorconfig`");
+                }
                 if !unstable_options.is_empty() {
                     let s = if unstable_options.len() == 1 { "" } else { "s" };
                     return Err(format_err!(
@@ -762,6 +773,10 @@ impl CliOptions for GetOptsOptions {
             .map(|version| Version::from_str(version).ok())
             .flatten()
     }
+
+    fn use_editorconfig(&self) -> bool {
+        self.unstable_features && self.use_editorconfig
+    }
 }
 
 fn edition_from_edition_str(edition_str: &str) -> Result<Edition> {
diff --git a/src/config/config_type.rs b/src/config/config_type.rs
index f559cc0d620..9508feb6ef0 100644
--- a/src/config/config_type.rs
+++ b/src/config/config_type.rs
@@ -100,7 +100,7 @@ macro_rules! create_config {
         // specify all properties of `Config`.
         // We first parse into `PartialConfig`, then create a default `Config`
         // and overwrite the properties with corresponding values from `PartialConfig`.
-        #[derive(Deserialize, Serialize, Clone)]
+        #[derive(Deserialize, Serialize, Clone, Default)]
         #[allow(unreachable_pub)]
         pub struct PartialConfig {
             $(pub $i: Option<<$ty as StyleEditionDefault>::ConfigType>),+
@@ -244,18 +244,26 @@ macro_rules! create_config {
                 CliConfigWasSet(self)
             }
 
-            fn fill_from_parsed_config(mut self, parsed: PartialConfig, dir: &Path) -> Config {
-            $(
-                if let Some(option_value) = parsed.$i {
-                    let option_stable = self.$i.3;
-                    if $crate::config::config_type::is_stable_option_and_value(
-                        stringify!($i), option_stable, &option_value
-                    ) {
-                        self.$i.1 = true;
-                        self.$i.2 = option_value;
+            /// Like `Self::fill_from_parsed_config`, but does not do any extra magic besides
+            /// filling in all config values defined in the given partial config.
+            #[allow(unreachable_pub)]
+            pub fn fill_from_partial_config(mut self, partial: PartialConfig) -> Config {
+                $(
+                    if let Some(option_value) = partial.$i {
+                        let option_stable = self.$i.3;
+                        if $crate::config::config_type::is_stable_option_and_value(
+                            stringify!($i), option_stable, &option_value
+                        ) {
+                            self.$i.1 = true;
+                            self.$i.2 = option_value;
+                        }
                     }
-                }
-            )+
+                )+
+                self
+            }
+
+            fn fill_from_parsed_config(mut self, parsed: PartialConfig, dir: &Path) -> Config {
+                self = self.fill_from_partial_config(parsed);
                 self.set_heuristics();
                 self.set_ignore(dir);
                 self.set_merge_imports();
diff --git a/src/config/editorconfig.rs b/src/config/editorconfig.rs
new file mode 100644
index 00000000000..f15cbd581a5
--- /dev/null
+++ b/src/config/editorconfig.rs
@@ -0,0 +1,102 @@
+//! This module adapts between .editorconfig values and rustfmt’s formatting options.
+
+use std::path::Path;
+
+use ec4rs::{
+    Properties, properties_of,
+    property::{
+        Charset, EndOfLine, FinalNewline, IndentSize, IndentStyle, MaxLineLen, TabWidth,
+        TrimTrailingWs,
+    },
+};
+
+use crate::{NewlineStyle, config::PartialConfig};
+
+/// Reads any applicable .editorconfig values for the given file,
+/// and converts it into rustfmt’s config options.
+/// Returns None if there is no applicable .editorconfig.
+pub fn editorconfig_configuration_for(
+    file: impl AsRef<Path>,
+) -> Result<Option<PartialConfig>, String> {
+    let mut properties = properties_of(file).map_err(|e| e.to_string())?;
+    properties.use_fallbacks();
+    Ok(Some(properties.try_into()?))
+}
+
+impl TryFrom<Properties> for PartialConfig {
+    type Error = String;
+
+    fn try_from(properties: Properties) -> Result<Self, Self::Error> {
+        let mut config = PartialConfig::default();
+
+        // 1. Ensure that "unconfigurable" keys have the values we expect, if present.
+        // Only utf-8 charsets are permitted.
+        let charset = get_editorconfig_property::<Charset>(&properties)?;
+        if let Some(charset) = charset {
+            if ![Charset::Utf8, Charset::Utf8Bom].contains(&charset) {
+                return Err(format!("Invalid charset '{charset}'",));
+            }
+        }
+        // Always true.
+        let trim_trailing_whitespace = get_editorconfig_property::<TrimTrailingWs>(&properties)?;
+        if let Some(TrimTrailingWs::Value(false)) = trim_trailing_whitespace {
+            return Err(format!("trim_trailing_whitespace must not be false",));
+        }
+        // Always true.
+        let insert_final_newline = get_editorconfig_property::<FinalNewline>(&properties)?;
+        if let Some(FinalNewline::Value(false)) = insert_final_newline {
+            return Err(format!("insert_final_newline must not be false",));
+        }
+
+        // 2. Actually parse configurable keys.
+        let indent_style = get_editorconfig_property::<IndentStyle>(&properties)?;
+        let indent_size = get_editorconfig_property::<IndentSize>(&properties)?;
+        let tab_width = get_editorconfig_property::<TabWidth>(&properties)?;
+        let end_of_line = get_editorconfig_property::<EndOfLine>(&properties)?;
+        let max_line_len = get_editorconfig_property::<MaxLineLen>(&properties)?;
+
+        if let Some(indent_style) = indent_style {
+            config.hard_tabs = Some(indent_style == IndentStyle::Tabs);
+        }
+        if let Some(IndentSize::Value(indent_size)) = indent_size {
+            config.tab_spaces = Some(indent_size);
+        }
+        // Note: If the tab width is not set, the specification says to use
+        //       "the tab size set by the editor."
+        //       We interpret this to mean "the default/fallback value",
+        //       and don’t specify tab_spaces in this case.
+        if let Some(IndentSize::UseTabWidth) = indent_size {
+            if let Some(TabWidth::Value(indent_size)) = tab_width {
+                config.tab_spaces = Some(indent_size);
+            }
+        }
+        if let Some(end_of_line) = end_of_line {
+            config.newline_style = match end_of_line {
+                EndOfLine::Lf => Some(NewlineStyle::Unix),
+                EndOfLine::CrLf => Some(NewlineStyle::Windows),
+                EndOfLine::Cr => return Err("'end_of_line=cr' is not supported".to_owned()),
+            };
+        }
+        if let Some(MaxLineLen::Value(max_line_len)) = max_line_len {
+            config.max_width = Some(max_line_len);
+        }
+
+        Ok(config)
+    }
+}
+
+/// Improved wrapper around [`ec4rs::Properties::get`].
+fn get_editorconfig_property<T: ec4rs::PropertyKey + ec4rs::PropertyValue>(
+    properties: &ec4rs::Properties,
+) -> Result<Option<T>, String> {
+    properties.get::<T>().map_or_else(
+        |raw| {
+            if raw.filter_unset().is_unset() {
+                Ok(None)
+            } else {
+                Err(format!("Invalid value {raw}"))
+            }
+        },
+        |value| Ok(Some(value)),
+    )
+}
diff --git a/src/config/mod.rs b/src/config/mod.rs
index a3f9842cd4f..d05bffb4bc4 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -8,6 +8,8 @@ use thiserror::Error;
 
 use crate::config::config_type::ConfigType;
 #[allow(unreachable_pub)]
+pub use crate::config::editorconfig::editorconfig_configuration_for;
+#[allow(unreachable_pub)]
 pub use crate::config::file_lines::{FileLines, FileName, Range};
 #[allow(unreachable_pub)]
 pub use crate::config::macro_names::MacroSelector;
@@ -20,6 +22,7 @@ pub(crate) mod config_type;
 #[allow(unreachable_pub)]
 pub(crate) mod options;
 
+pub(crate) mod editorconfig;
 pub(crate) mod file_lines;
 #[allow(unreachable_pub)]
 pub(crate) mod lists;
@@ -457,25 +460,31 @@ impl Config {
 
 /// Loads a config by checking the client-supplied options and if appropriate, the
 /// file system (including searching the file system for overrides).
+/// `file_path` is either a directory name, in which case the config is loaded only
+/// from the applicable rustfmt.toml.
+/// If it is a path to a Rust file, and the options request this, it may additionally
+/// load the config from the .editorconfig file.
 pub fn load_config<O: CliOptions>(
-    file_path: Option<&Path>,
+    file_or_directory: Option<&Path>,
     options: Option<O>,
 ) -> Result<(Config, Option<PathBuf>), Error> {
-    let (over_ride, edition, style_edition, version) = match options {
+    let (over_ride, edition, style_edition, version, use_editorconfig) = match options {
         Some(ref opts) => (
             config_path(opts)?,
             opts.edition(),
             opts.style_edition(),
             opts.version(),
+            opts.use_editorconfig(),
         ),
-        None => (None, None, None, None),
+        None => (None, None, None, None, false),
     };
+    let config_dir = file_or_directory.and_then(|f| if f.is_file() { f.parent() } else { Some(f) });
 
     let result = if let Some(over_ride) = over_ride {
         Config::from_toml_path(over_ride.as_ref(), edition, style_edition, version)
             .map(|p| (p, Some(over_ride.to_owned())))
-    } else if let Some(file_path) = file_path {
-        Config::from_resolved_toml_path(file_path, edition, style_edition, version)
+    } else if let Some(config_dir) = config_dir {
+        Config::from_resolved_toml_path(config_dir, edition, style_edition, version)
     } else {
         Ok((
             Config::default_for_possible_style_edition(style_edition, edition, version),
@@ -483,7 +492,22 @@ pub fn load_config<O: CliOptions>(
         ))
     };
 
+    let editorconfig = if use_editorconfig && file_or_directory.is_some_and(|f| f.is_file()) {
+        if let Some(file) = file_or_directory {
+            editorconfig_configuration_for(&file)
+                .map_err(|e| Error::other(format!("Invalid .editorconfig: {e}")))?
+        } else {
+            unreachable!()
+        }
+    } else {
+        None
+    };
+
     result.map(|(mut c, p)| {
+        if let Some(editorconfig) = editorconfig {
+            c = c.fill_from_partial_config(editorconfig);
+        }
+
         if let Some(options) = options {
             options.apply_to(&mut c);
         }
diff --git a/src/config/options.rs b/src/config/options.rs
index db48d99604a..0a3800c4bc1 100644
--- a/src/config/options.rs
+++ b/src/config/options.rs
@@ -465,6 +465,7 @@ pub trait CliOptions {
     /// It is ok if the returned path doesn't exist or is not canonicalized
     /// (i.e. the callers are expected to handle such cases).
     fn config_path(&self) -> Option<&Path>;
+    fn use_editorconfig(&self) -> bool;
     fn edition(&self) -> Option<Edition>;
     fn style_edition(&self) -> Option<StyleEdition>;
     fn version(&self) -> Option<Version>;
diff --git a/src/git-rustfmt/main.rs b/src/git-rustfmt/main.rs
index 64458420f59..c18baa7c5ec 100644
--- a/src/git-rustfmt/main.rs
+++ b/src/git-rustfmt/main.rs
@@ -98,6 +98,9 @@ impl CliOptions for NullOptions {
     fn version(&self) -> Option<Version> {
         unreachable!();
     }
+    fn use_editorconfig(&self) -> bool {
+        unreachable!()
+    }
 }
 
 fn uncommitted_files() -> Vec<String> {
diff --git a/src/lib.rs b/src/lib.rs
index 285fa26d00a..488526749ef 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -45,7 +45,7 @@ use crate::utils::indent_next_line;
 
 pub use crate::config::{
     CliOptions, Color, Config, Edition, EmitMode, FileLines, FileName, NewlineStyle, Range,
-    StyleEdition, Verbosity, Version, load_config,
+    StyleEdition, Verbosity, Version, editorconfig_configuration_for, load_config,
 };
 
 pub use crate::format_report_formatter::{FormatReportFormatter, FormatReportFormatterBuilder};
diff --git a/tests/editorconfig/errors/cr/.editorconfig b/tests/editorconfig/errors/cr/.editorconfig
new file mode 100644
index 00000000000..0d5b7bebe44
--- /dev/null
+++ b/tests/editorconfig/errors/cr/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: 'end_of_line=cr' is not supported
+
+root = true
+
+[*.rs]
+end_of_line = cr
diff --git a/tests/editorconfig/errors/cr/main.rs b/tests/editorconfig/errors/cr/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/cr/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-charset/.editorconfig b/tests/editorconfig/errors/invalid-charset/.editorconfig
new file mode 100644
index 00000000000..cf1690d651f
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-charset/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value javascript-or-something-idk
+
+root = true
+
+[*.rs]
+charset = javascript-or-something-idk
diff --git a/tests/editorconfig/errors/invalid-charset/main.rs b/tests/editorconfig/errors/invalid-charset/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-charset/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-editorconfig/.editorconfig b/tests/editorconfig/errors/invalid-editorconfig/.editorconfig
new file mode 100644
index 00000000000..b1c14ec3e9e
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-editorconfig/.editorconfig
@@ -0,0 +1,5 @@
+# rustfmt-expect: Invalid .editorconfig
+
+[{asdjk...iiid}]
+charsetutf-8
+?????%%
diff --git a/tests/editorconfig/errors/invalid-editorconfig/main.rs b/tests/editorconfig/errors/invalid-editorconfig/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-editorconfig/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-eol/.editorconfig b/tests/editorconfig/errors/invalid-eol/.editorconfig
new file mode 100644
index 00000000000..85a73ca2745
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-eol/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value invalid
+
+root = true
+
+[*.rs]
+end_of_line = invalid
diff --git a/tests/editorconfig/errors/invalid-eol/main.rs b/tests/editorconfig/errors/invalid-eol/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-eol/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-indent-size/.editorconfig b/tests/editorconfig/errors/invalid-indent-size/.editorconfig
new file mode 100644
index 00000000000..653da65ad09
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-indent-size/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value garbage
+
+root = true
+
+[*.rs]
+indent_size = garbage
diff --git a/tests/editorconfig/errors/invalid-indent-size/main.rs b/tests/editorconfig/errors/invalid-indent-size/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-indent-size/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-indent-style/.editorconfig b/tests/editorconfig/errors/invalid-indent-style/.editorconfig
new file mode 100644
index 00000000000..72ae818c9fc
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-indent-style/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value owo
+
+root = true
+
+[*.rs]
+indent_style = owo
diff --git a/tests/editorconfig/errors/invalid-indent-style/main.rs b/tests/editorconfig/errors/invalid-indent-style/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-indent-style/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-insert-final-newline/.editorconfig b/tests/editorconfig/errors/invalid-insert-final-newline/.editorconfig
new file mode 100644
index 00000000000..a006ac8a758
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-insert-final-newline/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value *biscuits*
+
+root = true
+
+[*.rs]
+insert_final_newline = *biscuits*
diff --git a/tests/editorconfig/errors/invalid-insert-final-newline/main.rs b/tests/editorconfig/errors/invalid-insert-final-newline/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-insert-final-newline/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-max-line-len/.editorconfig b/tests/editorconfig/errors/invalid-max-line-len/.editorconfig
new file mode 100644
index 00000000000..df6772e9cee
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-max-line-len/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value uwu
+
+root = true
+
+[*.rs]
+max_line_length = uwu
diff --git a/tests/editorconfig/errors/invalid-max-line-len/main.rs b/tests/editorconfig/errors/invalid-max-line-len/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-max-line-len/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-tab-width/.editorconfig b/tests/editorconfig/errors/invalid-tab-width/.editorconfig
new file mode 100644
index 00000000000..0400860da34
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-tab-width/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value mrrrp
+
+root = true
+
+[*.rs]
+tab_width = mrrrp
diff --git a/tests/editorconfig/errors/invalid-tab-width/main.rs b/tests/editorconfig/errors/invalid-tab-width/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-tab-width/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/invalid-trim-trailing-ws/.editorconfig b/tests/editorconfig/errors/invalid-trim-trailing-ws/.editorconfig
new file mode 100644
index 00000000000..2b178944ac1
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-trim-trailing-ws/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid value *paws*
+
+root = true
+
+[*.rs]
+trim_trailing_whitespace = *paws*
diff --git a/tests/editorconfig/errors/invalid-trim-trailing-ws/main.rs b/tests/editorconfig/errors/invalid-trim-trailing-ws/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/invalid-trim-trailing-ws/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/unsupported-charset/.editorconfig b/tests/editorconfig/errors/unsupported-charset/.editorconfig
new file mode 100644
index 00000000000..93cd18fa7f4
--- /dev/null
+++ b/tests/editorconfig/errors/unsupported-charset/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: Invalid charset 'latin1'
+
+root = true
+
+[*.rs]
+charset = latin1
diff --git a/tests/editorconfig/errors/unsupported-charset/main.rs b/tests/editorconfig/errors/unsupported-charset/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/unsupported-charset/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/unsupported-insert-final-newline/.editorconfig b/tests/editorconfig/errors/unsupported-insert-final-newline/.editorconfig
new file mode 100644
index 00000000000..32a5aca86e5
--- /dev/null
+++ b/tests/editorconfig/errors/unsupported-insert-final-newline/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: insert_final_newline must not be false
+
+root = true
+
+[*.rs]
+insert_final_newline = false
diff --git a/tests/editorconfig/errors/unsupported-insert-final-newline/main.rs b/tests/editorconfig/errors/unsupported-insert-final-newline/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/unsupported-insert-final-newline/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/errors/unsupported-trim-trailing-ws/.editorconfig b/tests/editorconfig/errors/unsupported-trim-trailing-ws/.editorconfig
new file mode 100644
index 00000000000..420eb6908b3
--- /dev/null
+++ b/tests/editorconfig/errors/unsupported-trim-trailing-ws/.editorconfig
@@ -0,0 +1,6 @@
+# rustfmt-expect: Invalid .editorconfig: trim_trailing_whitespace must not be false
+
+root = true
+
+[*.rs]
+trim_trailing_whitespace = false
diff --git a/tests/editorconfig/errors/unsupported-trim-trailing-ws/main.rs b/tests/editorconfig/errors/unsupported-trim-trailing-ws/main.rs
new file mode 100644
index 00000000000..2a778e4ea1a
--- /dev/null
+++ b/tests/editorconfig/errors/unsupported-trim-trailing-ws/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+
+}
diff --git a/tests/editorconfig/main.rs b/tests/editorconfig/main.rs
new file mode 100644
index 00000000000..d2adc343224
--- /dev/null
+++ b/tests/editorconfig/main.rs
@@ -0,0 +1,112 @@
+#![allow(unused)] // on stable
+
+use rustfmt_config_proc_macro::nightly_only_test;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::{env, fs};
+
+use tempfile::TempDir;
+
+fn rustfmt_binary() -> PathBuf {
+    let mut me = env::current_exe().expect("failed to get current executable");
+    // Chop of the test name.
+    me.pop();
+
+    // Handle Cargo's old and new filesystem layouts
+    // * v1: `target/<profile>/deps/test-bin-[HASH][EXE]`
+    // * v2: `target/<profile>/build/<pkgname>/[HASH]/out/test-bin-[HASH][EXE]`
+    if me.ends_with("deps") {
+        // Chop off `deps`.
+        me.pop();
+    } else if me.ends_with("out") {
+        // Chop off `out`.
+        me.pop();
+        // Chop off `<hash>`.
+        me.pop();
+        // Chop off `<pkgname>`.
+        me.pop();
+        // Chop off `build`.
+        me.pop();
+    }
+
+    me.push("rustfmt");
+    assert!(
+        me.is_file() || me.with_extension("exe").is_file(),
+        "{}",
+        "no rustfmt bin, try running `cargo build --locked` or `cargo build --locked --release` \
+        before testing"
+    );
+    me
+}
+
+/// Run rustfmt and return its output.
+fn rustfmt(args: &[&str]) -> (String, String) {
+    let rustfmt = rustfmt_binary();
+    let cmd = rustfmt;
+
+    match Command::new(&cmd).args(args).output() {
+        Ok(output) => (
+            String::from_utf8(output.stdout).expect("utf-8"),
+            String::from_utf8(output.stderr).expect("utf-8"),
+        ),
+        Err(e) => panic!("failed to run `{cmd:?} {args:?}`: {e}"),
+    }
+}
+
+#[nightly_only_test]
+#[test]
+fn integration() {
+    let source_base_path = Path::new("tests/editorconfig/source");
+    let target_base_path = Path::new("tests/editorconfig/target");
+    for test_directory in source_base_path.read_dir().unwrap() {
+        let source_directory = test_directory.unwrap().path();
+        let target_directory = target_base_path.join(source_directory.file_name().unwrap());
+        let temp_source_directory = TempDir::new().unwrap();
+        let output_directory = temp_source_directory.path();
+        for required_file in ["main.rs", ".editorconfig"] {
+            fs::copy(
+                source_directory.join(required_file),
+                output_directory.join(required_file),
+            )
+            .unwrap();
+        }
+        let _ = rustfmt(&[
+            "--unstable-features",
+            "--use-editorconfig",
+            output_directory.join("main.rs").to_string_lossy().as_ref(),
+        ]);
+
+        let reference_source = fs::read_to_string(target_directory.join("main.rs")).unwrap();
+        let result_source = fs::read_to_string(output_directory.join("main.rs")).unwrap();
+        assert_eq!(result_source, reference_source);
+        drop(temp_source_directory);
+    }
+}
+
+#[nightly_only_test]
+#[test]
+fn integration_errors() {
+    let base_path = Path::new("tests/editorconfig/errors");
+    for test_directory in base_path.read_dir().unwrap() {
+        let test_directory = test_directory.unwrap().path();
+        let (_, stderr) = rustfmt(&[
+            "--unstable-features",
+            "--use-editorconfig",
+            "--check",
+            test_directory.join("main.rs").to_string_lossy().as_ref(),
+        ]);
+        println!("{stderr}");
+        let editorconfig = fs::read_to_string(test_directory.join(".editorconfig")).unwrap();
+        let expected_error = editorconfig
+            .lines()
+            .next()
+            .unwrap()
+            .strip_prefix("# rustfmt-expect: ");
+        if let Some(expected_error) = expected_error {
+            println!("Checking contents of '{stderr}' for '{expected_error}'…");
+            assert!(stderr.contains(expected_error));
+        } else {
+            assert!(stderr.is_empty());
+        }
+    }
+}
diff --git a/tests/editorconfig/source/basic/.editorconfig b/tests/editorconfig/source/basic/.editorconfig
new file mode 100644
index 00000000000..b51566ce847
--- /dev/null
+++ b/tests/editorconfig/source/basic/.editorconfig
@@ -0,0 +1,8 @@
+root = true
+
+# Default Rust settings
+[*.rs]
+indent_size = 4
+indent_style = space
+end_of_line = lf
+charset = utf-8
diff --git a/tests/editorconfig/source/basic/main.rs b/tests/editorconfig/source/basic/main.rs
new file mode 100644
index 00000000000..5f0a31a6d32
--- /dev/null
+++ b/tests/editorconfig/source/basic/main.rs
@@ -0,0 +1,10 @@
+fn    main () {   /* badly formatted file */}
+
+        const    WHAT_IS_GOING_ON    : u32 =     
+
+
+
+    3
+
+
+                        ;
\ No newline at end of file
diff --git a/tests/editorconfig/source/eol-crlf/.editorconfig b/tests/editorconfig/source/eol-crlf/.editorconfig
new file mode 100644
index 00000000000..6000b8ea418
--- /dev/null
+++ b/tests/editorconfig/source/eol-crlf/.editorconfig
@@ -0,0 +1,6 @@
+root = true
+
+[*]
+# Make Bill Gates happy UwU
+end_of_line = crlf
+charset = utf-8-bom
diff --git a/tests/editorconfig/source/eol-crlf/main.rs b/tests/editorconfig/source/eol-crlf/main.rs
new file mode 100644
index 00000000000..c98f638a3b6
--- /dev/null
+++ b/tests/editorconfig/source/eol-crlf/main.rs
@@ -0,0 +1,10 @@
+// Note: The source version of this file has `\n` (LF) line endings, the target has `\r\n` (CRLF).
+
+fn main() {
+    let value = 5;
+    if value == 0 {
+        println!("meow");
+    } else {
+        println!("owo");
+    }
+}
diff --git a/tests/editorconfig/source/indent-size/.editorconfig b/tests/editorconfig/source/indent-size/.editorconfig
new file mode 100644
index 00000000000..b8c0648b313
--- /dev/null
+++ b/tests/editorconfig/source/indent-size/.editorconfig
@@ -0,0 +1,4 @@
+root = true
+
+[*.rs]
+indent_size = 7
diff --git a/tests/editorconfig/source/indent-size/main.rs b/tests/editorconfig/source/indent-size/main.rs
new file mode 100644
index 00000000000..c0dc3c762a8
--- /dev/null
+++ b/tests/editorconfig/source/indent-size/main.rs
@@ -0,0 +1,8 @@
+fn main()  {
+    let value = 5;
+    if value == 0 {
+        println!("meow");
+    } else {
+        println!("owo");
+    }
+}
diff --git a/tests/editorconfig/source/max-line-len/.editorconfig b/tests/editorconfig/source/max-line-len/.editorconfig
new file mode 100644
index 00000000000..ba3391264b2
--- /dev/null
+++ b/tests/editorconfig/source/max-line-len/.editorconfig
@@ -0,0 +1,4 @@
+root = true
+
+[*]
+max_line_length = 40
diff --git a/tests/editorconfig/source/max-line-len/main.rs b/tests/editorconfig/source/max-line-len/main.rs
new file mode 100644
index 00000000000..ce2fcb9825d
--- /dev/null
+++ b/tests/editorconfig/source/max-line-len/main.rs
@@ -0,0 +1,4 @@
+fn main()  {
+    // Should be wrapped due to max_line_len.
+    let value = 5940930490 + 2398329284308320 - 83498439734589374 + 29304920934029034 * 20934829384928340 / 234820984309234;
+}
diff --git a/tests/editorconfig/source/tab-indent/.editorconfig b/tests/editorconfig/source/tab-indent/.editorconfig
new file mode 100644
index 00000000000..b39b7e54800
--- /dev/null
+++ b/tests/editorconfig/source/tab-indent/.editorconfig
@@ -0,0 +1,4 @@
+root = true
+
+[*]
+indent_style = tab
diff --git a/tests/editorconfig/source/tab-indent/main.rs b/tests/editorconfig/source/tab-indent/main.rs
new file mode 100644
index 00000000000..c0dc3c762a8
--- /dev/null
+++ b/tests/editorconfig/source/tab-indent/main.rs
@@ -0,0 +1,8 @@
+fn main()  {
+    let value = 5;
+    if value == 0 {
+        println!("meow");
+    } else {
+        println!("owo");
+    }
+}
diff --git a/tests/editorconfig/source/tab-size/.editorconfig b/tests/editorconfig/source/tab-size/.editorconfig
new file mode 100644
index 00000000000..b69e994d0bb
--- /dev/null
+++ b/tests/editorconfig/source/tab-size/.editorconfig
@@ -0,0 +1,6 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = tab
+tab_width = 2
diff --git a/tests/editorconfig/source/tab-size/main.rs b/tests/editorconfig/source/tab-size/main.rs
new file mode 100644
index 00000000000..c0dc3c762a8
--- /dev/null
+++ b/tests/editorconfig/source/tab-size/main.rs
@@ -0,0 +1,8 @@
+fn main()  {
+    let value = 5;
+    if value == 0 {
+        println!("meow");
+    } else {
+        println!("owo");
+    }
+}
diff --git a/tests/editorconfig/target/basic/main.rs b/tests/editorconfig/target/basic/main.rs
new file mode 100644
index 00000000000..ea7fc5ba503
--- /dev/null
+++ b/tests/editorconfig/target/basic/main.rs
@@ -0,0 +1,4 @@
+fn main() { /* badly formatted file */
+}
+
+const WHAT_IS_GOING_ON: u32 = 3;
diff --git a/tests/editorconfig/target/eol-crlf/main.rs b/tests/editorconfig/target/eol-crlf/main.rs
new file mode 100644
index 00000000000..d6cae17f033
--- /dev/null
+++ b/tests/editorconfig/target/eol-crlf/main.rs
@@ -0,0 +1,10 @@
+// Note: The source version of this file has `\n` (LF) line endings, the target has `\r\n` (CRLF).
+
+fn main() {
+    let value = 5;
+    if value == 0 {
+        println!("meow");
+    } else {
+        println!("owo");
+    }
+}
diff --git a/tests/editorconfig/target/indent-size/main.rs b/tests/editorconfig/target/indent-size/main.rs
new file mode 100644
index 00000000000..3eac300d1d2
--- /dev/null
+++ b/tests/editorconfig/target/indent-size/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+       let value = 5;
+       if value == 0 {
+              println!("meow");
+       } else {
+              println!("owo");
+       }
+}
diff --git a/tests/editorconfig/target/max-line-len/main.rs b/tests/editorconfig/target/max-line-len/main.rs
new file mode 100644
index 00000000000..d95a230c1e9
--- /dev/null
+++ b/tests/editorconfig/target/max-line-len/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    // Should be wrapped due to max_line_len.
+    let value = 5940930490
+        + 2398329284308320
+        - 83498439734589374
+        + 29304920934029034
+            * 20934829384928340
+            / 234820984309234;
+}
diff --git a/tests/editorconfig/target/tab-indent/main.rs b/tests/editorconfig/target/tab-indent/main.rs
new file mode 100644
index 00000000000..82319edb8b8
--- /dev/null
+++ b/tests/editorconfig/target/tab-indent/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+	let value = 5;
+	if value == 0 {
+		println!("meow");
+	} else {
+		println!("owo");
+	}
+}
diff --git a/tests/editorconfig/target/tab-size/main.rs b/tests/editorconfig/target/tab-size/main.rs
new file mode 100644
index 00000000000..708f98048e0
--- /dev/null
+++ b/tests/editorconfig/target/tab-size/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+  let value = 5;
+  if value == 0 {
+    println!("meow");
+  } else {
+    println!("owo");
+  }
+}
diff --git a/tests/rustfmt/main.rs b/tests/rustfmt/main.rs
index ee972d8a6af..db5720abc3b 100644
--- a/tests/rustfmt/main.rs
+++ b/tests/rustfmt/main.rs
@@ -217,6 +217,8 @@ fn rustfmt_nightly_usage_text() {
                             whitespaces (unstable).
             --skip-children 
                             Don't reformat child modules (unstable).
+            --use-editorconfig 
+                            Respect .editorconfig settings for Rust source files.
         -v, --verbose       Print verbose output
         -q, --quiet         Print less output
         -V, --version       Show version information