diff --git a/vllm/model_executor/models/diffusion_gemma.py b/vllm/model_executor/models/diffusion_gemma.py
index 84d52fb5ba3b..5495a41587b3 100644
--- a/vllm/model_executor/models/diffusion_gemma.py
+++ b/vllm/model_executor/models/diffusion_gemma.py
@@ -250,6 +250,8 @@ def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
         self.lm_head = ParallelLMHead(
             num_embeddings=text_config.vocab_size,
             embedding_dim=text_config.hidden_size,
+            quant_config=vllm_config.quant_config,
+            prefix=maybe_prefix(prefix, "lm_head"),
         )
 
         if text_config.tie_word_embeddings: