diff --git a/src/ssl.c b/src/ssl.c
index 264f2c04ec..6b9bee1fc6 100644
--- a/src/ssl.c
+++ b/src/ssl.c
@@ -3418,7 +3418,7 @@ int  wolfSSL_set1_groups(WOLFSSL* ssl, int* groups, int count)
 #ifdef HAVE_ALPN
 
 WOLFSSL_ABI
-int wolfSSL_UseALPN(WOLFSSL* ssl, char *protocol_name_list,
+int wolfSSL_UseALPN(WOLFSSL* ssl, const char *protocol_name_list,
                     word32 protocol_name_listSz, byte options)
 {
     char    *list, *ptr, **token;
diff --git a/wolfssl/ssl.h b/wolfssl/ssl.h
index 90f711589e..fbb905d1fc 100644
--- a/wolfssl/ssl.h
+++ b/wolfssl/ssl.h
@@ -3967,7 +3967,7 @@ typedef int (*CallbackALPNSelect)(WOLFSSL* ssl, const unsigned char** out,
 #endif
 
 WOLFSSL_ABI WOLFSSL_API int wolfSSL_UseALPN(WOLFSSL* ssl,
-                                char *protocol_name_list,
+                                const char *protocol_name_list,
                                 unsigned int protocol_name_listSz,
                                 unsigned char options);