diff --git a/.github/workflows/post-release-to-x.yml b/.github/workflows/post-release-to-x.yml
new file mode 100644
index 0000000..d8d0492
--- /dev/null
+++ b/.github/workflows/post-release-to-x.yml
@@ -0,0 +1,62 @@
+name: Post release to X
+
+on:
+  release:
+    types: [published]
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: Print the X post text without posting.
+        required: true
+        default: true
+        type: boolean
+      release_name:
+        description: Release name for the test post.
+        required: true
+        default: Test Release
+        type: string
+      release_version:
+        description: Release tag/version for the test post.
+        required: true
+        default: v0.0.0-test
+        type: string
+      release_url:
+        description: Release URL for the test post.
+        required: true
+        default: https://github.com/example-org/example-repo/releases/tag/v0.0.0-test
+        type: string
+
+permissions:
+  contents: read
+
+concurrency:
+  group: x-release-${{ github.event.release.id }}
+  cancel-in-progress: false
+
+jobs:
+  post-release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Post release to X
+        env:
+          X_API_KEY: ${{ secrets.X_API_KEY }}
+          X_API_KEY_SECRET: ${{ secrets.X_API_KEY_SECRET }}
+          X_ACCESS_TOKEN: ${{ secrets.X_ACCESS_TOKEN }}
+          X_ACCESS_TOKEN_SECRET: ${{ secrets.X_ACCESS_TOKEN_SECRET }}
+          X_POST_DRY_RUN: ${{ github.event_name == 'workflow_dispatch' && inputs.dry_run || 'false' }}
+          X_INCLUDE_PRERELEASES: "true"
+          X_POST_HASHTAGS: ""
+          X_POST_TEMPLATE: "{repo} released {version}: {name}\\n{url}"
+          RELEASE_REPO: ${{ github.event_name == 'workflow_dispatch' && github.repository || '' }}
+          RELEASE_NAME: ${{ github.event_name == 'workflow_dispatch' && inputs.release_name || '' }}
+          RELEASE_VERSION: ${{ github.event_name == 'workflow_dispatch' && inputs.release_version || '' }}
+          RELEASE_URL: ${{ github.event_name == 'workflow_dispatch' && inputs.release_url || '' }}
+        run: node scripts/post-github-release-to-x.mjs
diff --git a/scripts/post-github-release-to-x.mjs b/scripts/post-github-release-to-x.mjs
new file mode 100644
index 0000000..64183d4
--- /dev/null
+++ b/scripts/post-github-release-to-x.mjs
@@ -0,0 +1,208 @@
+import crypto from "node:crypto";
+import fs from "node:fs";
+
+const X_POST_URL = "https://api.x.com/2/tweets";
+const MAX_POST_CHARS = 280;
+
+function requireEnv(name) {
+  const value = process.env[name];
+  if (!value) {
+    throw new Error(`Missing required environment variable: ${name}`);
+  }
+  return value;
+}
+
+function parseBoolean(value, fallback = false) {
+  if (value === undefined || value === "") return fallback;
+  return ["1", "true", "yes", "on"].includes(value.toLowerCase());
+}
+
+function loadGitHubEvent() {
+  if (process.env.RELEASE_REPO && process.env.RELEASE_VERSION && process.env.RELEASE_URL) {
+    return {
+      action: "published",
+      release: {
+        draft: false,
+        prerelease: parseBoolean(process.env.RELEASE_PRERELEASE, false),
+        name: process.env.RELEASE_NAME || process.env.RELEASE_VERSION,
+        tag_name: process.env.RELEASE_VERSION,
+        html_url: process.env.RELEASE_URL,
+      },
+      repository: {
+        name: process.env.RELEASE_REPO.split("/").at(-1),
+        full_name: process.env.RELEASE_REPO,
+      },
+    };
+  }
+
+  const eventPath = process.env.GITHUB_EVENT_PATH;
+  if (!eventPath) {
+    throw new Error("GITHUB_EVENT_PATH is not set. In GitHub Actions this is set automatically for release events.");
+  }
+
+  return JSON.parse(fs.readFileSync(eventPath, "utf8"));
+}
+
+function normalizeRelease(event) {
+  const release = event.release;
+  const repository = event.repository;
+
+  if (!release || !repository) {
+    throw new Error("GitHub event does not contain release and repository data.");
+  }
+
+  return {
+    action: event.action,
+    draft: Boolean(release.draft),
+    prerelease: Boolean(release.prerelease),
+    name: release.name || release.tag_name,
+    version: release.tag_name || release.name,
+    url: release.html_url,
+    repo: repository.full_name || repository.name,
+  };
+}
+
+function renderTemplate(template, release) {
+  return template
+    .replaceAll("{repo}", release.repo)
+    .replaceAll("{version}", release.version)
+    .replaceAll("{name}", release.name)
+    .replaceAll("{url}", release.url)
+    .replaceAll("\\n", "\n");
+}
+
+function compactWhitespace(text) {
+  return text
+    .split("\n")
+    .map((line) => line.trim())
+    .filter(Boolean)
+    .join("\n");
+}
+
+function fitPost(text) {
+  if (text.length <= MAX_POST_CHARS) return text;
+
+  const urlMatch = text.match(/https?:\/\/\S+$/);
+  const url = urlMatch?.[0] || "";
+  const suffix = url ? `\n${url}` : "";
+  const allowed = MAX_POST_CHARS - suffix.length - 1;
+
+  if (allowed < 20) {
+    return text.slice(0, MAX_POST_CHARS - 1) + "…";
+  }
+
+  return `${text.slice(0, allowed).trimEnd()}…${suffix}`;
+}
+
+function percentEncode(value) {
+  return encodeURIComponent(value)
+    .replaceAll("!", "%21")
+    .replaceAll("'", "%27")
+    .replaceAll("(", "%28")
+    .replaceAll(")", "%29")
+    .replaceAll("*", "%2A");
+}
+
+function oauthHeader({ method, url, apiKey, apiSecret, accessToken, accessTokenSecret }) {
+  const oauthParams = {
+    oauth_consumer_key: apiKey,
+    oauth_nonce: crypto.randomBytes(16).toString("hex"),
+    oauth_signature_method: "HMAC-SHA1",
+    oauth_timestamp: Math.floor(Date.now() / 1000).toString(),
+    oauth_token: accessToken,
+    oauth_version: "1.0",
+  };
+
+  const normalizedParams = Object.entries(oauthParams)
+    .sort(([a], [b]) => a.localeCompare(b))
+    .map(([key, value]) => `${percentEncode(key)}=${percentEncode(value)}`)
+    .join("&");
+
+  const signatureBase = [
+    method.toUpperCase(),
+    percentEncode(url),
+    percentEncode(normalizedParams),
+  ].join("&");
+
+  const signingKey = `${percentEncode(apiSecret)}&${percentEncode(accessTokenSecret)}`;
+  const signature = crypto.createHmac("sha1", signingKey).update(signatureBase).digest("base64");
+
+  return `OAuth ${Object.entries({ ...oauthParams, oauth_signature: signature })
+    .sort(([a], [b]) => a.localeCompare(b))
+    .map(([key, value]) => `${percentEncode(key)}="${percentEncode(value)}"`)
+    .join(", ")}`;
+}
+
+async function postToX(text) {
+  const apiKey = requireEnv("X_API_KEY");
+  const apiSecret = requireEnv("X_API_KEY_SECRET");
+  const accessToken = requireEnv("X_ACCESS_TOKEN");
+  const accessTokenSecret = requireEnv("X_ACCESS_TOKEN_SECRET");
+
+  const response = await fetch(X_POST_URL, {
+    method: "POST",
+    headers: {
+      Authorization: oauthHeader({
+        method: "POST",
+        url: X_POST_URL,
+        apiKey,
+        apiSecret,
+        accessToken,
+        accessTokenSecret,
+      }),
+      "Content-Type": "application/json",
+    },
+    body: JSON.stringify({ text }),
+  });
+
+  const body = await response.text();
+  if (!response.ok) {
+    throw new Error(`X API request failed with ${response.status}: ${body}`);
+  }
+
+  return JSON.parse(body);
+}
+
+async function main() {
+  const dryRun = parseBoolean(process.env.X_POST_DRY_RUN, false);
+  const includePrereleases = parseBoolean(process.env.X_INCLUDE_PRERELEASES, true);
+  const template = process.env.X_POST_TEMPLATE || "{repo} released {version}: {name}\\n{url}";
+  const hashtags = process.env.X_POST_HASHTAGS || "";
+
+  const event = loadGitHubEvent();
+  const release = normalizeRelease(event);
+
+  if (release.action && release.action !== "published") {
+    console.log(`Skipping release action "${release.action}".`);
+    return;
+  }
+
+  if (release.draft) {
+    console.log("Skipping draft release.");
+    return;
+  }
+
+  if (release.prerelease && !includePrereleases) {
+    console.log("Skipping prerelease because X_INCLUDE_PRERELEASES=false.");
+    return;
+  }
+
+  const text = fitPost(compactWhitespace(`${renderTemplate(template, release)}\n${hashtags}`));
+
+  if (dryRun) {
+    console.log("Dry run. This would be posted to X:");
+    console.log("---");
+    console.log(text);
+    console.log("---");
+    console.log(`Character count: ${text.length}`);
+    return;
+  }
+
+  const result = await postToX(text);
+  console.log(`Posted to X: https://x.com/i/web/status/${result.data.id}`);
+}
+
+main().catch((error) => {
+  console.error(error.message);
+  process.exit(1);
+});