diff --git a/patsy/eval.py b/patsy/eval.py
index 12ce0d4..0919787 100644
--- a/patsy/eval.py
+++ b/patsy/eval.py
@@ -18,6 +18,7 @@
 import tokenize
 import ast
 import numbers
+import pytest
 from patsy import PatsyError
 from patsy.util import PushbackAdapter, no_pickling, assert_no_pickling
 from patsy.tokens import pretty_untokenize, normalize_token_spacing, python_tokenize
@@ -423,6 +424,13 @@ def test_EvalEnvironment_subset():
     pytest.raises(NameError, subset_bc.eval, "a")
 
 
+@pytest.mark.skipif(
+    sys.version_info >= (3, 13),
+    reason=(
+        "`frame.f_locals` may return write-through proxies in Python 3.13+, "
+        "breaking direct comparison by ids."
+    ),
+)
 def test_EvalEnvironment_eq():
     # Two environments are eq only if they refer to exactly the same
     # global/local dicts