diff --git a/CMakeLists.txt b/CMakeLists.txt
index 767cc064..f5a98fa1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -434,6 +434,8 @@ if(CMAKE_C_COMPILER_ID MATCHES GNU|Clang)
                 -Wmissing-prototypes
                 -Wmissing-declarations
                 -Wredundant-decls
+                -Wimplicit-fallthrough
+                -Wimplicit-fallthrough=5
 
                 -Wc99-compat
                 -Wc11-extensions
diff --git a/configure.ac b/configure.ac
index c3447b2e..3eef0aea 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1299,6 +1299,8 @@ AS_IF([test "$GCC" = yes], [
 			-Wmissing-prototypes \
 			-Wmissing-declarations \
 			-Wredundant-decls \
+			-Wimplicit-fallthrough \
+			-Wimplicit-fallthrough=5 \
 			\
 			-Wc99-compat \
 			-Wc11-extensions \