diff --git a/tensorrt_llm/_torch/modules/fused_moe/mega_moe/mega_moe_deepgemm.py b/tensorrt_llm/_torch/modules/fused_moe/mega_moe/mega_moe_deepgemm.py
index d8f037e02d49..51328e6a4427 100644
--- a/tensorrt_llm/_torch/modules/fused_moe/mega_moe/mega_moe_deepgemm.py
+++ b/tensorrt_llm/_torch/modules/fused_moe/mega_moe/mega_moe_deepgemm.py
@@ -290,6 +290,15 @@ def __init__(
             or getattr(model_config, "max_num_tokens", 0)
             or 4096
         )
+        # Under attention DP, ``ModelConfig`` pre-multiplies
+        # ``moe_max_num_tokens`` by ``dp_size``. The DG SymmBuffer further
+        # scales the pool by ``num_ranks`` (= ep_size, which equals dp_size
+        # in the supported full-ADP topology asserted above). Without this
+        # divide the buffer is sized as ``dp_size * ep_size *
+        # max_num_tokens``, doubling the EP factor and exploding HBM (see
+        # ``layout::Workspace`` / ``get_num_max_pool_tokens`` in DG).
+        if self.use_dp and self.ep_size > 1:
+            self.max_num_tokens = max(1, (self.max_num_tokens + self.ep_size - 1) // self.ep_size)
 
         # Resolve the EP ProcessGroup at module construction — creating a
         # group at forward time would be collective on a non-synchronous