diff --git a/changelog/11638.trivial.rst b/changelog/11638.trivial.rst
new file mode 100644
index 00000000000..374960b8925
--- /dev/null
+++ b/changelog/11638.trivial.rst
@@ -0,0 +1 @@
+Fixed the selftests to pass correctly if ``FORCE_COLOR``, ``NO_COLOR`` or ``PY_COLORS`` is set in the calling environment.
diff --git a/testing/conftest.py b/testing/conftest.py
index 6a50e810fbd..bcb05339b62 100644
--- a/testing/conftest.py
+++ b/testing/conftest.py
@@ -31,6 +31,17 @@ def set_column_width(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setenv("COLUMNS", "80")
 
 
+@pytest.fixture(autouse=True)
+def reset_colors(monkeypatch: pytest.MonkeyPatch) -> None:
+    """
+    Reset all color-related variables to prevent them from affecting internal pytest output
+    in tests that depend on it.
+    """
+    monkeypatch.delenv("PY_COLORS", raising=False)
+    monkeypatch.delenv("NO_COLOR", raising=False)
+    monkeypatch.delenv("FORCE_COLOR", raising=False)
+
+
 @pytest.hookimpl(wrapper=True, tryfirst=True)
 def pytest_collection_modifyitems(items) -> Generator[None, None, None]:
     """Prefer faster tests.