diff --git a/docs/design/attention_backends.md b/docs/design/attention_backends.md
index 9d524a489be..8062ce237db 100644
--- a/docs/design/attention_backends.md
+++ b/docs/design/attention_backends.md
@@ -205,7 +205,7 @@ hardware and configuration.
 
 | Backend | Description | Dtypes | Compute Cap. | Notes |
 | ------- | ----------- | ------ | ------------ | ----- |
-| `FLASH_ATTN`‡ | FlashAttention varlen (FA2/FA3/FA4) | fp16, bf16 | Any | (qk_nope_head_dim=128, qk_rope_head_dim=64, v_head_dim=128) (FA2/FA3/FA4) or (qk_nope_head_dim=192, qk_rope_head_dim=64, v_head_dim=256) (FA2/FA3 only) |
+| `FLASH_ATTN`‡ | FlashAttention varlen (FA2/FA3/FA4) | fp16, bf16 | Any | (qk_nope_head_dim=128, qk_rope_head_dim=64, v_head_dim=128) (FA2/FA3/FA4) or (qk_nope_head_dim=64, qk_rope_head_dim=64, v_head_dim=128) (FA2/FA3/FA4) or (qk_nope_head_dim=192, qk_rope_head_dim=64, v_head_dim=256) (FA2/FA3 only) |
 | `TRTLLM_RAGGED` | TensorRT-LLM ragged attention | fp16, bf16 | 10.x | (qk_nope_head_dim=128, qk_rope_head_dim=64, v_head_dim=128) or (qk_nope_head_dim=192, qk_rope_head_dim=64, v_head_dim=256) only |
 | `FLASHINFER` | FlashInfer CUTLASS backend | fp16, bf16 | 10.x | (qk_nope_head_dim=128, qk_rope_head_dim=64, v_head_dim=128) only |
 | `TOKENSPEED_MLA` | | fp16, bf16 | 10.x | (qk_nope_head_dim=128, qk_rope_head_dim=64, v_head_dim=128) only |
diff --git a/tests/v1/attention/test_mla_prefill_selector.py b/tests/v1/attention/test_mla_prefill_selector.py
index 8677197b7a5..d82397591f7 100644
--- a/tests/v1/attention/test_mla_prefill_selector.py
+++ b/tests/v1/attention/test_mla_prefill_selector.py
@@ -125,8 +125,8 @@ class TestGetMLAPrefillBackend:
 
     @pytest.mark.parametrize(
         ("qk_nope_head_dim", "v_head_dim"),
-        [(128, 128), (192, 256)],
-        ids=["deepseek", "glm"],
+        [(128, 128), (192, 256), (64, 128)],
+        ids=["deepseek", "glm", "mistral_s4"],
     )
     def test_auto_selection_on_hopper(self, qk_nope_head_dim: int, v_head_dim: int):
         try:
diff --git a/vllm/v1/attention/backends/mla/prefill/flash_attn.py b/vllm/v1/attention/backends/mla/prefill/flash_attn.py
index afc4efa1ae9..30c0c6d8a68 100644
--- a/vllm/v1/attention/backends/mla/prefill/flash_attn.py
+++ b/vllm/v1/attention/backends/mla/prefill/flash_attn.py
@@ -63,11 +63,16 @@ class FlashAttnPrefillBackend(MLAPrefillBackend):
             qk_rope_head_dim=64,
             v_head_dim=256,
         )
+        dims_mistral_s4 = MLADimensions(
+            qk_nope_head_dim=64,
+            qk_rope_head_dim=64,
+            v_head_dim=128,
+        )
         fa_version = get_flash_attn_version()
         if fa_version == 4:
-            return mla_dimensions == dims_deepseek
+            return mla_dimensions in [dims_deepseek, dims_mistral_s4]
         else:
-            return mla_dimensions in [dims_deepseek, dims_glm]
+            return mla_dimensions in [dims_deepseek, dims_glm, dims_mistral_s4]
 
     def __init__(
         self,