diff --git a/Makefile b/Makefile
index 7f1113286..5018a35e0 100644
--- a/Makefile
+++ b/Makefile
@@ -25,7 +25,7 @@ ifdef MSVC
 	uname_S := Windows
 endif
 
-CFLAGS = -g -O2 -Wall
+CFLAGS = -g -O2 -Wall -Wextra
 OS     = unix
 
 EXTRA_SRC =
diff --git a/tests/Makefile b/tests/Makefile
index e5ff26740..e3059f59c 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -10,7 +10,7 @@ ifdef MSVC
 	uname_S := Windows
 endif
 
-CFLAGS = -g -O2 -Wall
+CFLAGS = -g -O2 -Wall -Wextra
 LIBS   = -L.. -lgit2 -lz
 OS     = unix