diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index a17faa1..8283702 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2425,6 +2425,19 @@
 #include "mbedtls/target_config.h"
 #endif
 
+/*
+ * Allow user to override any previous default.
+ *
+ * Use two macro names for that, as:
+ * - with yotta the prefix YOTTA_CFG_ is forced
+ * - without yotta is looks weird to have a YOTTA prefix.
+ */
+#if defined(YOTTA_CFG_MBEDTLS_USER_CONFIG_FILE)
+#include YOTTA_CFG_MBEDTLS_USER_CONFIG_FILE
+#elif defined(MBEDTLS_USER_CONFIG_FILE)
+#include MBEDTLS_USER_CONFIG_FILE
+#endif
+
 #include "check_config.h"
 
 #endif /* MBEDTLS_CONFIG_H */