diff --git a/src/detect.js b/src/detect.js
index 3d64f98..0606794 100644
--- a/src/detect.js
+++ b/src/detect.js
@@ -80,6 +80,51 @@ async function detectGoMod(root, output) {
   }
 }
 
+async function detectCargoToml(root, output) {
+  const content = await read(root, "Cargo.toml");
+  if (!content) return;
+  const lines = content.split(/\r?\n/);
+
+  for (const [index, line] of lines.entries()) {
+    const match = line.match(/^\s*rust-version\s*=\s*["']([^"']+)["']/);
+    if (match) {
+      add(output, "rust", "Cargo.toml", match[1], index + 1);
+    }
+  }
+}
+
+async function detectRustToolchain(root, output) {
+  const content = await read(root, "rust-toolchain.toml");
+  if (!content) return;
+  const lines = content.split(/\r?\n/);
+
+  for (const [index, line] of lines.entries()) {
+    const match = line.match(/^\s*channel\s*=\s*["']([^"']+)["']/);
+    if (match) {
+      add(output, "rust", "rust-toolchain.toml", match[1], index + 1);
+    }
+  }
+}
+
+async function detectGoMod(root, output) {
+  const content = await read(root, "go.mod");
+  if (!content) return;
+
+  const lines = content.split(/\r?\n/);
+
+  for (const [index, line] of lines.entries()) {
+    const go = line.match(/^\s*go\s+(\S+)/);
+    if (go) {
+      add(output, "go", "go.mod", go[1], index + 1);
+    }
+
+    const toolchain = line.match(/^\s*toolchain\s+go(\S+)/);
+    if (toolchain) {
+      add(output, "go", "go.mod", toolchain[1], index + 1);
+    }
+  }
+}
+
 async function detectToolVersions(root, output) {
   const content = await read(root, ".tool-versions");
   if (!content) return;
@@ -115,7 +160,7 @@ async function detectDockerfiles(root, output) {
     const content = await read(root, entry.name);
     for (const [index, line] of content.split(/\r?\n/).entries()) {
       const match = line.match(
-        /^\s*FROM\s+(?:[^/\s]+\/)?(node|python|golang):([^\s@]+)/i,
+        /^\s*FROM\s+(?:[^/\s]+\/)?(node|python|golang|rust):([^\s@]+)/i,
       );
       if (match)
         add(
@@ -151,9 +196,11 @@ async function detectGithubActions(root, output) {
     let remaining = 0;
 
     for (const [index, line] of lines.entries()) {
-      const action = line.match(/uses:\s*actions\/setup-(node|python|go)@/i);
+      const action = line.match(
+        /uses:\s*(?:actions\/setup-(node|python|go)|dtolnay\/rust-toolchain)@/i,
+      );
       if (action) {
-        runtime = action[1].toLowerCase();
+        runtime = action[1] ? action[1].toLowerCase() : "rust";
         remaining = 12;
         continue;
       }
@@ -162,7 +209,9 @@ async function detectGithubActions(root, output) {
         continue;
       }
       remaining -= 1;
-      const declared = line.match(/(?:node-version|python-version|go-version):\s*["']?([^"'#\s]+)/i);
+      const declared = line.match(
+        /(?:node-version|python-version|go-version|toolchain):\s*["']?([^"'#\s]+)/i,
+      );
       if (runtime && declared && !declared[1].startsWith("${{")) {
         add(output, runtime, file, declared[1], index + 1);
         runtime = null;
@@ -178,6 +227,8 @@ export async function detectDeclarations(root) {
     detectPackageJson(root, output),
     detectPyproject(root, output),
     detectGoMod(root, output),
+    detectCargoToml(root, output),
+    detectRustToolchain(root, output),
     detectToolVersions(root, output),
     detectMise(root, output),
     detectDockerfiles(root, output),
diff --git a/src/format.js b/src/format.js
index 70a9273..bb5f3cf 100644
--- a/src/format.js
+++ b/src/format.js
@@ -6,6 +6,7 @@ const LABELS = {
   go: "Go",
   node: "Node.js",
   python: "Python",
+  rust: "Rust",
 };
 
 export function formatHuman(result) {
diff --git a/test/detect.test.js b/test/detect.test.js
index ec7ab70..d15073d 100644
--- a/test/detect.test.js
+++ b/test/detect.test.js
@@ -6,17 +6,18 @@ import { inspect } from "../src/index.js";
 
 const here = path.dirname(fileURLToPath(import.meta.url));
 
-test("finds aligned Node.js and Python declarations", async () => {
+test("finds aligned Node.js, golang, Rust, and Python declarations", async () => {
   const result = await inspect(path.join(here, "fixtures", "aligned"));
 
   assert.equal(result.ok, true);
   assert.deepEqual(
     result.runtimes.map((runtime) => runtime.runtime),
-    ["go", "node", "python"],
+    ["go", "node", "python", "rust"],
   );
   assert.equal(result.runtimes[0].declarations.length, 3);
   assert.equal(result.runtimes[1].declarations.length, 5);
   assert.equal(result.runtimes[2].declarations.length, 5);
+  assert.equal(result.runtimes[3].declarations.length, 4);
 });
 
 test("finds Docker and project-file drift", async () => {
@@ -24,12 +25,20 @@ test("finds Docker and project-file drift", async () => {
   assert.equal(result.ok, false);
   assert.deepEqual(
     result.runtimes.map((runtime) => runtime.runtime),
-    ["go", "node"],
+    ["go", "node", "rust"],
   );
+  // Node.js, golang, and Rust are all misaligned
+  const node = result.runtimes.find((runtime) => runtime.runtime === "node");
+  assert.ok(node);
+  assert.equal(node.ok, false);
   const go = result.runtimes.find((runtime) => runtime.runtime === "go");
 
   assert.ok(go);
   assert.equal(go.ok, false);
+
+  const rust = result.runtimes.find((runtime) => runtime.runtime === "rust");
+  assert.ok(rust);
+  assert.equal(rust.ok, false);
 });
 
 test("returns an empty success for a directory with no declarations", async () => {
diff --git a/test/fixtures/aligned/.github/workflows/ci.yml b/test/fixtures/aligned/.github/workflows/ci.yml
index d932b85..80d14d9 100644
--- a/test/fixtures/aligned/.github/workflows/ci.yml
+++ b/test/fixtures/aligned/.github/workflows/ci.yml
@@ -14,3 +14,8 @@ jobs:
       - uses: actions/setup-go@v5
         with:
           go-version: "1.24"
+  rust:
+    steps:
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: "1.81.0"
diff --git a/test/fixtures/aligned/Cargo.toml b/test/fixtures/aligned/Cargo.toml
new file mode 100644
index 0000000..0331b24
--- /dev/null
+++ b/test/fixtures/aligned/Cargo.toml
@@ -0,0 +1,5 @@
+[package]
+name = "example"
+version = "0.1.0"
+edition = "2021"
+rust-version = "1.81"
diff --git a/test/fixtures/aligned/Dockerfile b/test/fixtures/aligned/Dockerfile
index 82caf45..837dd2e 100644
--- a/test/fixtures/aligned/Dockerfile
+++ b/test/fixtures/aligned/Dockerfile
@@ -1,2 +1,3 @@
 FROM node:22-alpine AS web
 FROM python:3.12-slim AS worker
+FROM rust:1.81.0
diff --git a/test/fixtures/aligned/rust-toolchain.toml b/test/fixtures/aligned/rust-toolchain.toml
new file mode 100644
index 0000000..1de01fa
--- /dev/null
+++ b/test/fixtures/aligned/rust-toolchain.toml
@@ -0,0 +1,2 @@
+[toolchain]
+channel = "1.81.0"
diff --git a/test/fixtures/drift/Cargo.toml b/test/fixtures/drift/Cargo.toml
new file mode 100644
index 0000000..0331b24
--- /dev/null
+++ b/test/fixtures/drift/Cargo.toml
@@ -0,0 +1,5 @@
+[package]
+name = "example"
+version = "0.1.0"
+edition = "2021"
+rust-version = "1.81"
diff --git a/test/fixtures/drift/Dockerfile b/test/fixtures/drift/Dockerfile
index 67a885b..373bd7c 100644
--- a/test/fixtures/drift/Dockerfile
+++ b/test/fixtures/drift/Dockerfile
@@ -1,2 +1,3 @@
 FROM node:20-alpine
 FROM golang:1.23
+FROM rust:1.82
diff --git a/test/fixtures/drift/rust-toolchain.toml b/test/fixtures/drift/rust-toolchain.toml
new file mode 100644
index 0000000..1de01fa
--- /dev/null
+++ b/test/fixtures/drift/rust-toolchain.toml
@@ -0,0 +1,2 @@
+[toolchain]
+channel = "1.81.0"