diff --git a/relay/channel/openai/adaptor.go b/relay/channel/openai/adaptor.go
index 29a8f34949c..79d570d21ea 100644
--- a/relay/channel/openai/adaptor.go
+++ b/relay/channel/openai/adaptor.go
@@ -333,6 +333,7 @@ func (a *Adaptor) ConvertOpenAIRequest(c *gin.Context, info *relaycommon.RelayIn
 		if strings.HasPrefix(info.UpstreamModelName, "gpt-5") {
 			request.Temperature = nil
 			request.TopP = nil
+			request.THINKING = nil
 			request.LogProbs = nil
 		}