diff --git a/Tools/ardupilotwaf/boards.py b/Tools/ardupilotwaf/boards.py
index 732d58031a..8c6b4b057d 100644
--- a/Tools/ardupilotwaf/boards.py
+++ b/Tools/ardupilotwaf/boards.py
@@ -118,6 +118,7 @@ class Board:
             '-Werror=shadow',
             '-Werror=return-type',
             '-Werror=unused-result',
+            '-Werror=unused-variable',
             '-Werror=narrowing',
             '-Werror=attributes',
             '-Werror=overflow',