diff --git a/.github/workflows/ci_msw.yml b/.github/workflows/ci_msw.yml
index 15a1475950..dc449add8c 100644
--- a/.github/workflows/ci_msw.yml
+++ b/.github/workflows/ci_msw.yml
@@ -151,6 +151,7 @@ jobs:
           cmake -G "MinGW Makefiles" \
                 -DCMAKE_C_COMPILER=clang.exe \
                 -DCMAKE_CXX_COMPILER=clang++.exe \
+                -DCMAKE_CXX_FLAGS=-Werror \
                 -DCMAKE_BUILD_TYPE=Release \
                 -DwxBUILD_SAMPLES=ALL \
                 -DwxBUILD_TESTS=ALL \