diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b3a66ad44..71da543a6 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -26,6 +26,8 @@ jobs:
             os: macos-15-intel
           - target: x86_64-unknown-linux-gnu
             os: ubuntu-22.04
+          - target: aarch64-unknown-linux-gnu
+            os: ubuntu-22.04-arm
     runs-on: ${{ matrix.os }}
     timeout-minutes: 45
     steps:
@@ -87,7 +89,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [macos-14, macos-15-intel, ubuntu-22.04]
+        os: [macos-14, macos-15-intel, ubuntu-22.04, ubuntu-22.04-arm]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 15
     env:
diff --git a/README.md b/README.md
index 3885554d2..0c73fb4b7 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ diffr main...HEAD -- src/      # merge-base comparison
 
 ## Installation
 
-CLI and terminal UI (Apple Silicon macOS, Intel macOS, and x64 Linux):
+CLI and terminal UI (Apple Silicon macOS, Intel macOS, and x64/ARM64 Linux):
 
 ```sh
 brew install devdotfast/tap/diffr
diff --git a/diffr-ts/README.md b/diffr-ts/README.md
index 1f88c0445..48a361b32 100644
--- a/diffr-ts/README.md
+++ b/diffr-ts/README.md
@@ -29,6 +29,9 @@ Keep these files in sync:
 
 ## Release
 
+Linux ARM64 fetch support requires a release containing an `aarch64-unknown-linux-gnu`
+archive and regenerated pins; the bundled 0.1.5 pins do not include it.
+
 After tagging the matching Rust release and building with `cargo build --locked`,
 run from `diffr-ts`. New pins select the CLI-only release archives; older pins
 continue to use the full archives:
diff --git a/diffr-ts/bin/fetch.mjs b/diffr-ts/bin/fetch.mjs
index 79420b87f..6ce74518f 100755
--- a/diffr-ts/bin/fetch.mjs
+++ b/diffr-ts/bin/fetch.mjs
@@ -7,7 +7,7 @@ import { fileURLToPath } from "node:url";
 import { parseArgs } from "node:util";
 
 const root = resolve(dirname(fileURLToPath(import.meta.url)), "..");
-const targets = { "darwin-arm64": "aarch64-apple-darwin", "darwin-x64": "x86_64-apple-darwin", "linux-x64": "x86_64-unknown-linux-gnu" };
+const targets = { "darwin-arm64": "aarch64-apple-darwin", "darwin-x64": "x86_64-apple-darwin", "linux-x64": "x86_64-unknown-linux-gnu", "linux-arm64": "aarch64-unknown-linux-gnu" };
 
 try {
   await main();
diff --git a/diffr-ts/scripts/pin.mjs b/diffr-ts/scripts/pin.mjs
index 70df95dfe..b858ec44c 100755
--- a/diffr-ts/scripts/pin.mjs
+++ b/diffr-ts/scripts/pin.mjs
@@ -7,7 +7,7 @@ import { fileURLToPath } from "node:url";
 const here = dirname(fileURLToPath(import.meta.url));
 const root = join(here, "..");
 const version = JSON.parse(readFileSync(join(root, "package.json"), "utf8")).version;
-const targets = ["aarch64-apple-darwin", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+const targets = ["aarch64-apple-darwin", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu", "aarch64-unknown-linux-gnu"];
 const artifact = "diffr-cli";
 const sha256 = {};
 for (const target of targets) {
diff --git a/diffr-ts/src/fetch.test.ts b/diffr-ts/src/fetch.test.ts
index 6e78ae5ad..282902a9c 100644
--- a/diffr-ts/src/fetch.test.ts
+++ b/diffr-ts/src/fetch.test.ts
@@ -6,14 +6,15 @@ import { join } from "node:path";
 
 const fetchScript = join(import.meta.dir, "..", "bin", "fetch.mjs");
 const { version } = JSON.parse(readFileSync(join(import.meta.dir, "..", "package.json"), "utf8"));
-const targets: Record<string, string> = { "darwin-arm64": "aarch64-apple-darwin", "darwin-x64": "x86_64-apple-darwin", "linux-x64": "x86_64-unknown-linux-gnu" };
+const targets: Record<string, string> = { "darwin-arm64": "aarch64-apple-darwin", "darwin-x64": "x86_64-apple-darwin", "linux-x64": "x86_64-unknown-linux-gnu", "linux-arm64": "aarch64-unknown-linux-gnu" };
 const target = targets[`${process.platform}-${process.arch}`];
 const dirs: string[] = [];
 afterEach(() => {
   for (const dir of dirs.splice(0)) rmSync(dir, { recursive: true, force: true });
 });
 
-function fixture(entry = "diffr", artifact?: string) {
+function fixture(entry = "diffr", artifact?: string, platform = process.platform, arch = process.arch) {
+  const target = targets[`${platform}-${arch}`];
   if (!target) throw new Error("Fetch tests require a supported release platform");
   const dir = mkdtempSync(join(tmpdir(), "diffr-fetch-test-"));
   dirs.push(dir);
@@ -25,9 +26,11 @@ function fixture(entry = "diffr", artifact?: string) {
   const pins = join(dir, "pins.json");
   writeFileSync(pins, JSON.stringify({ version, artifact, sha256: { [target]: hash } }));
   const mock = join(dir, "mock.mjs");
-  // Intercept only the network boundary, leaving the actual CLI and tar intact.
+  // Mock the platform and network, leaving the actual CLI and tar intact.
   writeFileSync(mock, `
     import { readFileSync, writeFileSync } from "node:fs";
+    Object.defineProperty(process, "platform", { value: ${JSON.stringify(platform)} });
+    Object.defineProperty(process, "arch", { value: ${JSON.stringify(arch)} });
     globalThis.fetch = async (url) => {
       writeFileSync(${JSON.stringify(join(dir, "requested"))}, url);
       if (process.env.FETCH_FAILURE) throw new Error("offline");
@@ -120,6 +123,20 @@ test("missing option values fail clearly", () => {
   expect(f.run(["--into"]).code).toBe(1);
 });
 
+test("Linux ARM64 downloads and stamps the aarch64 release", () => {
+  const f = fixture("diffr", "diffr-cli", "linux", "arm64");
+  const result = f.run(["--required"]);
+  expect(result.code, result.err).toBe(0);
+  expect(readFileSync(join(f.dir, "requested"), "utf8")).toBe(
+    `https://github.com/devdotfast/diffr/releases/download/${version}/diffr-cli-${version}-aarch64-unknown-linux-gnu.tar.gz`,
+  );
+  expect(readFileSync(join(f.into, "diffr"), "utf8")).toBe(f.content);
+  expect(JSON.parse(readFileSync(join(f.into, "diffr.stamp.json"), "utf8"))).toEqual({
+    version, target: "aarch64-unknown-linux-gnu",
+  });
+  expect(f.run(["--check"], true).code).toBe(0);
+});
+
 test("CLI-only pins download the CLI archive", () => {
   const f = fixture("diffr", "diffr-cli");
   const result = f.run(["--required"]);
diff --git a/scripts/release.py b/scripts/release.py
index fad9aa55f..ecc44e4c8 100644
--- a/scripts/release.py
+++ b/scripts/release.py
@@ -6,7 +6,7 @@
 import subprocess
 import tarfile
 
-TARGETS = ("aarch64-apple-darwin", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu")
+TARGETS = ("aarch64-apple-darwin", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu", "aarch64-unknown-linux-gnu")
 ROOT = Path(__file__).resolve().parent.parent
 
 
@@ -55,9 +55,14 @@ def formula(version, output):
   end
 
   on_linux do
-    depends_on arch: :x86_64
-    url "{url}-x86_64-unknown-linux-gnu.tar.gz"
-    sha256 "{checksums[archive_name(version, 'x86_64-unknown-linux-gnu')]}"
+    on_arm do
+      url "{url}-aarch64-unknown-linux-gnu.tar.gz"
+      sha256 "{checksums[archive_name(version, 'aarch64-unknown-linux-gnu')]}"
+    end
+    on_intel do
+      url "{url}-x86_64-unknown-linux-gnu.tar.gz"
+      sha256 "{checksums[archive_name(version, 'x86_64-unknown-linux-gnu')]}"
+    end
   end
 
   def install