diff --git a/include/mbedtls/cmac.h b/include/mbedtls/cmac.h
index c196793..9d42b3f 100644
--- a/include/mbedtls/cmac.h
+++ b/include/mbedtls/cmac.h
@@ -28,6 +28,12 @@
 #ifndef MBEDTLS_CMAC_H
 #define MBEDTLS_CMAC_H
 
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
 #include "cipher.h"
 
 #ifdef __cplusplus