diff --git a/.changeset/fix-invalid-value-doubled-expected.md b/.changeset/fix-invalid-value-doubled-expected.md
new file mode 100644
index 00000000000..a8e9deaeedd
--- /dev/null
+++ b/.changeset/fix-invalid-value-doubled-expected.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Fix doubled `Expected: Expected ...` prefixes in CLI `InvalidValue` error messages, closes #6312.
diff --git a/packages/effect/src/unstable/cli/CliError.ts b/packages/effect/src/unstable/cli/CliError.ts
index ae58094514c..2ff929399d3 100644
--- a/packages/effect/src/unstable/cli/CliError.ts
+++ b/packages/effect/src/unstable/cli/CliError.ts
@@ -362,13 +362,16 @@ export class InvalidValue extends Schema.TaggedErrorClass<InvalidValue>(
    * @since 4.0.0
    */
   override get message() {
+    const expectation = this.expected.startsWith("Expected ") || this.expected.startsWith("Expected:")
+      ? this.expected
+      : `Expected: ${this.expected}`
     if (this.kind === "argument") {
-      return `Invalid value for argument <${this.option}>: "${this.value}". Expected: ${this.expected}`
+      return `Invalid value for argument <${this.option}>: "${this.value}". ${expectation}`
     }
     if (this.value.length === 0) {
-      return `Missing value for flag --${this.option}. Expected: ${this.expected}`
+      return `Missing value for flag --${this.option}. ${expectation}`
     }
-    return `Invalid value for flag --${this.option}: "${this.value}". Expected: ${this.expected}`
+    return `Invalid value for flag --${this.option}: "${this.value}". ${expectation}`
   }
 }
 
diff --git a/packages/effect/src/unstable/cli/Primitive.ts b/packages/effect/src/unstable/cli/Primitive.ts
index a4c59201f14..4526a81af1e 100644
--- a/packages/effect/src/unstable/cli/Primitive.ts
+++ b/packages/effect/src/unstable/cli/Primitive.ts
@@ -304,7 +304,7 @@ export const choice = <A>(
     if (choiceMap.has(value)) {
       return Effect.succeed(choiceMap.get(value)!)
     }
-    return Effect.fail(`Expected ${validChoices}, got ${format(value)}`)
+    return Effect.fail(validChoices)
   })
   return Object.assign(primitive, { choiceKeys: choices.map(([key]) => key) })
 }
diff --git a/packages/effect/test/unstable/cli/Arguments.test.ts b/packages/effect/test/unstable/cli/Arguments.test.ts
index 7314bf37551..5c0f37788dc 100644
--- a/packages/effect/test/unstable/cli/Arguments.test.ts
+++ b/packages/effect/test/unstable/cli/Arguments.test.ts
@@ -156,7 +156,7 @@ describe("Command arguments", () => {
       expect(errorText).toMatchInlineSnapshot(`
         "
         ERROR
-          Invalid value for argument <count>: "not-a-number". Expected: Failed to parse integer: Expected an integer, got NaN"
+          Invalid value for argument <count>: "not-a-number". Expected a string representing a finite number, got "not-a-number""
       `)
     }).pipe(Effect.provide(TestLayer)))
 
diff --git a/packages/effect/test/unstable/cli/Command.test.ts b/packages/effect/test/unstable/cli/Command.test.ts
index 756ae223aaf..5dac07ac127 100644
--- a/packages/effect/test/unstable/cli/Command.test.ts
+++ b/packages/effect/test/unstable/cli/Command.test.ts
@@ -271,6 +271,27 @@ describe("Command", () => {
         }).pipe(Effect.provide(TestLayer)))
     }
 
+    it.effect("should render invalid choice values without doubling the Expected prefix", () =>
+      Effect.gen(function*() {
+        let invoked = false
+        const command = Command.make("demo", {
+          size: Flag.choice("size", ["small", "medium", "large"])
+        }, () =>
+          Effect.sync(() => {
+            invoked = true
+          }))
+
+        yield* Command.runWith(command, { version: "1.0.0" })(["--size", "bogus"]).pipe(Effect.ignore)
+
+        const stderr = yield* TestConsole.errorLines
+        assert.isFalse(invoked)
+        assert.isTrue(
+          stderr.some((line) =>
+            String(line).includes(`Invalid value for flag --size: "bogus". Expected: "small" | "medium" | "large"`)
+          )
+        )
+      }).pipe(Effect.provide(TestLayer)))
+
     it.effect("should execute handler with parsed config", () =>
       Effect.gen(function*() {
         const path = yield* Path.Path
diff --git a/packages/effect/test/unstable/cli/Errors.test.ts b/packages/effect/test/unstable/cli/Errors.test.ts
index 933502c431b..2fcb127de2a 100644
--- a/packages/effect/test/unstable/cli/Errors.test.ts
+++ b/packages/effect/test/unstable/cli/Errors.test.ts
@@ -147,4 +147,60 @@ describe("Command errors", () => {
       assert.strictEqual(output, "")
     })
   })
+
+  describe("InvalidValue", () => {
+    it("labels a bare expected description", () => {
+      const error = new CliError.InvalidValue({
+        option: "size",
+        value: "bogus",
+        expected: `"small" | "medium" | "large"`,
+        kind: "flag"
+      })
+
+      assert.strictEqual(
+        error.message,
+        `Invalid value for flag --size: "bogus". Expected: "small" | "medium" | "large"`
+      )
+    })
+
+    it("does not double the prefix for an Expected sentence", () => {
+      const error = new CliError.InvalidValue({
+        option: "count",
+        value: "3.14",
+        expected: "Expected an integer, got 3.14",
+        kind: "argument"
+      })
+
+      assert.strictEqual(
+        error.message,
+        `Invalid value for argument <count>: "3.14". Expected an integer, got 3.14`
+      )
+
+      const labeled = new CliError.InvalidValue({
+        option: "count",
+        value: "x",
+        expected: "Expected: an integer",
+        kind: "flag"
+      })
+
+      assert.strictEqual(
+        labeled.message,
+        `Invalid value for flag --count: "x". Expected: an integer`
+      )
+    })
+
+    it("does not double the prefix for a missing flag value", () => {
+      const error = new CliError.InvalidValue({
+        option: "count",
+        value: "",
+        expected: `Expected a string representing a finite number, got ""`,
+        kind: "flag"
+      })
+
+      assert.strictEqual(
+        error.message,
+        `Missing value for flag --count. Expected a string representing a finite number, got ""`
+      )
+    })
+  })
 })
diff --git a/packages/effect/test/unstable/cli/Primitive.test.ts b/packages/effect/test/unstable/cli/Primitive.test.ts
index 0b83b1ee630..f3e3706c5fc 100644
--- a/packages/effect/test/unstable/cli/Primitive.test.ts
+++ b/packages/effect/test/unstable/cli/Primitive.test.ts
@@ -214,9 +214,9 @@ describe("Primitive", () => {
           colorChoice,
           ["yellow", "purple", ""],
           [
-            `Expected "red" | "green" | "blue", got "yellow"`,
-            `Expected "red" | "green" | "blue", got "purple"`,
-            `Expected "red" | "green" | "blue", got ""`
+            `"red" | "green" | "blue"`,
+            `"red" | "green" | "blue"`,
+            `"red" | "green" | "blue"`
           ]
         ))