diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 9585e69..1b4bee3 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -496,6 +496,13 @@
 #define MBEDTLS_CIPHER_MODE_CBC
 
 /**
+ * \def MBEDTLS_CIPHER_MODE_OFB
+ *
+ * Enable Output Feedback mode (OFB) for symmetric ciphers.
+ */
+#define MBEDTLS_CIPHER_MODE_OFB
+
+/**
  * \def MBEDTLS_CIPHER_MODE_CFB
  *
  * Enable Cipher Feedback mode (CFB) for symmetric ciphers.