diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 57669a4..cc9da34 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -5790,7 +5790,7 @@
  * \param key_len     Length of the key to generate in bytes, must be at most
  *                    MBEDTLS_SSL_EXPORT_MAX_KEY_LEN (8160).
  * \param label       Label for which to generate the key of length label_len.
- * \param label_len   Length of label in bytes. Must be at most 250 in TLS 1.3.
+ * \param label_len   Length of label in bytes. Must be at most 249 in TLS 1.3.
  * \param context     Context of the key. Can be NULL if context_len or use_context is 0.
  * \param context_len Length of context. Must be < 2^16 in TLS 1.2.
  * \param use_context Indicates if a context should be used in deriving the key.