diff --git a/zorg/buildbot/builders/ClangBuilder.py b/zorg/buildbot/builders/ClangBuilder.py
index 9d261011b..23d936ce1 100644
--- a/zorg/buildbot/builders/ClangBuilder.py
+++ b/zorg/buildbot/builders/ClangBuilder.py
@@ -286,6 +286,7 @@ def _getClangCMakeBuildFactory(
         depends_on_projects.append('libunwind')
     if checkout_flang:
         depends_on_projects.append('flang')
+        depends_on_projects.append('flang-rt')
         depends_on_projects.append('mlir')
 
     f = LLVMBuildFactory(