How do you troubleshoot a GitHub Actions job stuck queued?

A job stuck in a "Queued" state almost always means GitHub can't find an available runner that matches the job's requirements, rather than the workflow itself being broken.

1. Check runner availability - for self-hosted runners, confirm at least one matching runner is online in Settings > Actions > Runners.
2. Check labels - if the job specifies custom runs-on labels, confirm a runner registered with those exact labels exists; a mismatch leaves the job unassignable.
3. Check concurrency limits - organizations and plans have limits on concurrent Actions jobs; if every slot is in use, new jobs queue instead of starting.
4. Check GitHub-hosted runner status - occasionally GitHub-hosted runner capacity is delayed platform-wide; GitHub's status page will show ongoing incidents.
5. Check billing/spending limits - organizations with a configured Actions spending limit will queue or block new jobs once that limit is reached.

Most stuck-queued cases resolve once the runner label mismatch, offline self-hosted runner, or concurrency ceiling is identified; a workflow YAML error normally fails fast with a clear error rather than leaving the job queued indefinitely.