diff --git a/evals/registry.py b/evals/registry.py
index 2d1c0fee1d..5926e2f9fd 100644
--- a/evals/registry.py
+++ b/evals/registry.py
@@ -85,11 +85,21 @@ def is_chat_model(model_name: str) -> bool:
         return False
 
     CHAT_MODEL_NAMES = {"gpt-3.5-turbo", "gpt-3.5-turbo-16k", "gpt-4", "gpt-4-32k"}
+    CHAT_MODEL_PREFIXES = {
+        "gpt-3.5-turbo-",
+        "gpt-4-",
+        "gpt-4o",
+        "gpt-4.1",
+        "gpt-4.5",
+        "o1",
+        "o3",
+        "o4",
+    }
 
     if model_name in CHAT_MODEL_NAMES:
         return True
 
-    for model_prefix in {"gpt-3.5-turbo-", "gpt-4-"}:
+    for model_prefix in CHAT_MODEL_PREFIXES:
         if model_name.startswith(model_prefix):
             return True
 
diff --git a/evals/registry_test.py b/evals/registry_test.py
index ef05316220..1e7bd341fc 100644
--- a/evals/registry_test.py
+++ b/evals/registry_test.py
@@ -1,4 +1,5 @@
-from evals.registry import is_chat_model, n_ctx_from_model_name
+from evals import OpenAIChatCompletionFn
+from evals.registry import Registry, is_chat_model, n_ctx_from_model_name
 
 
 def test_n_ctx_from_model_name():
@@ -27,6 +28,22 @@ def test_is_chat_model():
     assert is_chat_model("gpt-4-0613")
     assert is_chat_model("gpt-4-32k")
     assert is_chat_model("gpt-4-32k-0613")
+    assert is_chat_model("gpt-4o")
+    assert is_chat_model("gpt-4o-mini")
+    assert is_chat_model("gpt-4.1")
+    assert is_chat_model("gpt-4.1-mini")
+    assert is_chat_model("o1")
+    assert is_chat_model("o1-mini")
+    assert is_chat_model("o3-mini")
+    assert is_chat_model("o4-mini")
     assert not is_chat_model("text-davinci-003")
     assert not is_chat_model("gpt4-base")
     assert not is_chat_model("code-davinci-002")
+
+
+def test_make_completion_fn_uses_chat_completion_for_modern_chat_models():
+    registry = Registry()
+
+    completion_fn = registry.make_completion_fn("gpt-4o-mini")
+
+    assert isinstance(completion_fn, OpenAIChatCompletionFn)