diff --git a/openhands-sdk/openhands/sdk/llm/utils/model_features.py b/openhands-sdk/openhands/sdk/llm/utils/model_features.py
index cd8d8088d9..f82865fd38 100644
--- a/openhands-sdk/openhands/sdk/llm/utils/model_features.py
+++ b/openhands-sdk/openhands/sdk/llm/utils/model_features.py
@@ -66,6 +66,7 @@ class ModelFeatures:
     # Gemini 3 family
     "gemini-3-flash-preview",
     "gemini-3-pro-preview",
+    "gemini-3.1-pro-preview",
     # OpenAI GPT-5 family (includes mini variants)
     "gpt-5",
     # Anthropic Opus 4.5 and 4.6
diff --git a/tests/sdk/llm/test_model_features.py b/tests/sdk/llm/test_model_features.py
index 5e829dc342..1586ec4b69 100644
--- a/tests/sdk/llm/test_model_features.py
+++ b/tests/sdk/llm/test_model_features.py
@@ -35,6 +35,7 @@ def test_model_matches(name, pattern, expected):
         # Gemini 3 family
         ("gemini-3-pro-preview", True),
         ("gemini-3-flash-preview", True),
+        ("gemini-3.1-pro-preview", True),
         # GPT-5 family
         ("gpt-5.2", True),
         ("gpt-5.2-codex", True),