diff --git a/libcxx/utils/ci/run-buildbot b/libcxx/utils/ci/run-buildbot
--- a/libcxx/utils/ci/run-buildbot
+++ b/libcxx/utils/ci/run-buildbot
@@ -142,6 +142,8 @@
     git diff | tee ${BUILD_DIR}/generated_output.patch
     # Check if the diffs are empty, fail otherwise.
     ! grep -q '^--- a' ${BUILD_DIR}/generated_output.patch
+    # Check that no dependency cycles have been introduced.
+    python3 libcxx/utils/graph_header_deps.py >/dev/null
 ;;
 generic-cxx03)
     export CC=clang