diff --git a/vllm/platforms/rocm.py b/vllm/platforms/rocm.py
index 807e571..bbc642a 100644
--- a/vllm/platforms/rocm.py
+++ b/vllm/platforms/rocm.py
@@ -983,6 +983,12 @@ class RocmPlatform(Platform):
         major, minor = torch.cuda.get_device_capability(device_id)
         return DeviceCapability(major=major, minor=minor)
 
+    @classmethod
+    def is_device_capability_family(cls, capability: int, device_id: int = 0) -> bool:
+        # Families are a CUDA notion, and gfx majors collide with them (gfx1032 reads as
+        # 10.3, i.e. Blackwell sm_103): no CUDA family check may match a ROCm GPU.
+        return False
+
     @classmethod
     @with_amdsmi_context
     def is_fully_connected(cls, physical_device_ids: list[int]) -> bool: