diff --git a/changelog/12444.bugfix.rst b/changelog/12444.bugfix.rst
new file mode 100644
index 00000000000..6b94c887eda
--- /dev/null
+++ b/changelog/12444.bugfix.rst
@@ -0,0 +1 @@
+In :pr:`13046`, fixes a bug where the .approx method incorrectly reported all key-value pairs as mismatched when only one was incorrect in unordered dictionaries.
diff --git a/src/_pytest/python_api.py b/src/_pytest/python_api.py
index cbb2ff2b80a..3de6e5cb01f 100644
--- a/src/_pytest/python_api.py
+++ b/src/_pytest/python_api.py
@@ -254,9 +254,8 @@ def _repr_compare(self, other_side: Mapping[object, float]) -> list[str]:
         max_abs_diff = -math.inf
         max_rel_diff = -math.inf
         different_ids = []
-        for (approx_key, approx_value), other_value in zip(
-            approx_side_as_map.items(), other_side.values()
-        ):
+        for approx_key, approx_value in approx_side_as_map.items():
+            other_value = other_side.get(approx_key, None)
             if approx_value != other_value:
                 if approx_value.expected is not None and other_value is not None:
                     try:
diff --git a/testing/python/approx.py b/testing/python/approx.py
index 7eba4755c01..1e2d15d6cde 100644
--- a/testing/python/approx.py
+++ b/testing/python/approx.py
@@ -1022,6 +1022,17 @@ def test_strange_sequence(self):
         assert b == pytest.approx(a, abs=2)
         assert b != pytest.approx(a, abs=0.5)
 
+    def test_approx_unordered_dicts_with_mismatch(self):
+        """https://github.com/pytest-dev/pytest/pull/12445"""
+        dict1 = {"a": 1.0, "b": 1.0, "c": 3.1}
+        dict2 = {"b": 2.0, "a": 1.0, "c": 3.1}  # 'b' has a different value
+
+        with pytest.raises(
+            AssertionError,
+            match="Mismatched elements: 1 / 3:\n  Max absolute difference: 1.0\n",
+        ):
+            assert dict1 == pytest.approx(dict2)
+
 
 class MyVec3:  # incomplete
     """sequence like"""