diff --git a/websocket-sharp/WebSocket.cs b/websocket-sharp/WebSocket.cs
index e8256b37..39fe2283 100644
--- a/websocket-sharp/WebSocket.cs
+++ b/websocket-sharp/WebSocket.cs
@@ -3001,7 +3001,7 @@ namespace WebSocketSharp
     /// <paramref name="data"/> is <see langword="null"/>.
     /// </exception>
     /// <exception cref="ArgumentException">
-    /// <paramref name="data"/> could not be UTF8 encoded.
+    /// <paramref name="data"/> could not be UTF-8-encoded.
     /// </exception>
     public void SendAsync (string data, Action<bool> completed)
     {