diff --git a/tests/e2e/online_serving/test_sd3_expansion.py b/tests/e2e/online_serving/test_sd3_expansion.py
new file mode 100644
index 000000000..3ed5cc5f3
--- /dev/null
+++ b/tests/e2e/online_serving/test_sd3_expansion.py
@@ -0,0 +1,65 @@
+"""
+Tests for Stable Diffusion 3.5 medium model.
+"""
+
+import pytest
+
+from tests.conftest import (
+    OmniServer,
+    OmniServerParams,
+    OpenAIClientHandler,
+)
+from tests.utils import hardware_marks
+
+FOUR_CARD_FEATURE_MARKS = hardware_marks(res={"cuda": "L4"}, num_cards=4)
+POSITIVE_PROMPT = "A serene mountain landscape at sunset"
+NEGATIVE_PROMPT = "blurry, low quality, distorted"
+
+
+# For now, we only test one or two good configurations for this model to keep
+# the CI light. The test cases focus on the most common feature combinations
+# that provide good performance improvements.
+def _get_diffusion_feature_cases(model: str):
+    return [
+        # Cache-DiT + CFG Parallel + Tensor Parallel
+        pytest.param(
+            OmniServerParams(
+                model=model,
+                server_args=[
+                    "--cache-backend",
+                    "cache_dit",
+                    "--cfg-parallel-size",
+                    "2",
+                    "--tensor-parallel-size",
+                    "2",
+                ],
+            ),
+            marks=FOUR_CARD_FEATURE_MARKS,
+        ),
+    ]
+
+
+@pytest.mark.advanced_model
+@pytest.mark.diffusion
+@pytest.mark.parametrize(
+    "omni_server",
+    _get_diffusion_feature_cases(
+        model="stabilityai/stable-diffusion-3.5-medium",
+    ),
+    indirect=True,
+)
+def test_sd3_medium(omni_server: OmniServer, openai_client: OpenAIClientHandler):
+    request_config = {
+        "model": omni_server.model,
+        "messages": [{"role": "user", "content": POSITIVE_PROMPT}],
+        "extra_body": {
+            "height": 1024,
+            "width": 1024,
+            "num_inference_steps": 28,
+            "negative_prompt": NEGATIVE_PROMPT,
+            "guidance_scale": 4.5,
+            "seed": 42,
+        },
+    }
+
+    openai_client.send_diffusion_request(request_config)