diff --git a/vllm/engine/output_processor/multi_step.py b/vllm/engine/output_processor/multi_step.py
index c8b282b1a7676..99c2baf3f4df4 100644
--- a/vllm/engine/output_processor/multi_step.py
+++ b/vllm/engine/output_processor/multi_step.py
@@ -144,7 +144,7 @@ def process_outputs(self,
     def _process_decode_and_stop(self, seq: Sequence,
                                  sampling_params: SamplingParams) -> None:
         new_char_count = 0
-        if sampling_params.detokenize:
+        if sampling_params.detokenize and self.detokenizer:
             new_char_count = self.detokenizer.decode_sequence_inplace(
                 seq, sampling_params)