diff --git a/python/sglang/srt/server_args.py b/python/sglang/srt/server_args.py
index 2797e0670..678274a4c 100644
--- a/python/sglang/srt/server_args.py
+++ b/python/sglang/srt/server_args.py
@@ -1285,6 +1285,13 @@ class ServerArgs:
                     "Disable hybrid SWA memory for GPT-OSS model with trtllm_mha attention backend."
                 )
 
+            if self.speculative_algorithm is not None:
+                # TODO: fix spec with SWA memory cache
+                self.disable_hybrid_swa_memory = True
+                logger.warning(
+                    "Disable hybrid SWA memory for GPT-OSS model with speculative decoding."
+                )
+
             quant_method = get_quantization_config(hf_config)
             is_mxfp4_quant_format = quant_method == "mxfp4"
             if is_mxfp4_quant_format: