diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5335e9e1..8bd572a0 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -574,6 +574,7 @@ set(VALAC_OPTIONS
     --enable-checking
     --debug
     --enable-deprecated
+    --fatal-warnings
     ${EXTRA_VALA_OPTIONS}
 )