diff --git a/.github/workflows/build-tests-mac.yml b/.github/workflows/build-tests-mac.yml
index 090f1d69..2aef84ce 100644
--- a/.github/workflows/build-tests-mac.yml
+++ b/.github/workflows/build-tests-mac.yml
@@ -12,6 +12,14 @@ jobs:
   buildForAllPlatformsMacOS:
     name: ${{ matrix.targetPlatform }} on ${{ matrix.unityVersion }}
     runs-on: macos-latest
+    # A per-step timeout doesn't bound an action's own implicit post-run
+    # cleanup step (e.g. actions/cache@v4's cache-save), which is exactly
+    # what's been observed hanging here - real builds finish in well under
+    # 40m, but a hung "Post Run actions/cache@v4" step has left jobs stuck
+    # "in_progress" for 1.5h+. A job-level timeout is the only thing that
+    # bounds that too, converting a silent multi-hour hang into a clear,
+    # fast failure.
+    timeout-minutes: 60
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/build-tests-ubuntu.yml b/.github/workflows/build-tests-ubuntu.yml
index c0e6277d..3c9ece82 100644
--- a/.github/workflows/build-tests-ubuntu.yml
+++ b/.github/workflows/build-tests-ubuntu.yml
@@ -37,6 +37,10 @@ jobs:
   buildForAllPlatformsUbuntu:
     name: "${{ matrix.targetPlatform }} on ${{ matrix.unityVersion}}${{startsWith(matrix.buildProfile, 'Assets') && ' (via Build Profile)' || '' }}"
     runs-on: ubuntu-latest
+    # See build-tests-mac.yml's matching comment - a per-step timeout doesn't
+    # bound an action's own implicit post-run cleanup step, only a job-level
+    # timeout does.
+    timeout-minutes: 60
     # Known, disclosed gap (see #844's description and src/build-args.ts's own
     # header comment): the CLI always detects the Unity version from the
     # checked-out project's ProjectSettings/ProjectVersion.txt and has no flag
diff --git a/.github/workflows/build-tests-windows.yml b/.github/workflows/build-tests-windows.yml
index a3db753a..e3286a9c 100644
--- a/.github/workflows/build-tests-windows.yml
+++ b/.github/workflows/build-tests-windows.yml
@@ -12,6 +12,10 @@ jobs:
   buildForAllPlatformsWindows:
     name: ${{ matrix.targetPlatform }} on ${{ matrix.unityVersion }}
     runs-on: windows-2022
+    # See build-tests-mac.yml's matching comment - a per-step timeout doesn't
+    # bound an action's own implicit post-run cleanup step, only a job-level
+    # timeout does.
+    timeout-minutes: 60
     strategy:
       fail-fast: false
       matrix: