@@ -927,8 +927,14 @@ def retry_handler(_request: httpx.Request) -> httpx.Response:
     def test_proxy_environment_variables(self, monkeypatch: pytest.MonkeyPatch) -> None:
         # Test that the proxy environment variables are set correctly
         monkeypatch.setenv("HTTPS_PROXY", "https://example.org")
-        # Delete in case our environment has this set
+        # Delete in case our environment has any proxy env vars set
         monkeypatch.delenv("HTTP_PROXY", raising=False)
+        monkeypatch.delenv("ALL_PROXY", raising=False)
+        monkeypatch.delenv("NO_PROXY", raising=False)
+        monkeypatch.delenv("http_proxy", raising=False)
+        monkeypatch.delenv("https_proxy", raising=False)
+        monkeypatch.delenv("all_proxy", raising=False)
+        monkeypatch.delenv("no_proxy", raising=False)
 
         client = DefaultHttpxClient()
 
@@ -1821,8 +1827,14 @@ async def test_get_platform(self) -> None:
     async def test_proxy_environment_variables(self, monkeypatch: pytest.MonkeyPatch) -> None:
         # Test that the proxy environment variables are set correctly
         monkeypatch.setenv("HTTPS_PROXY", "https://example.org")
-        # Delete in case our environment has this set
+        # Delete in case our environment has any proxy env vars set
         monkeypatch.delenv("HTTP_PROXY", raising=False)
+        monkeypatch.delenv("ALL_PROXY", raising=False)
+        monkeypatch.delenv("NO_PROXY", raising=False)
+        monkeypatch.delenv("http_proxy", raising=False)
+        monkeypatch.delenv("https_proxy", raising=False)
+        monkeypatch.delenv("all_proxy", raising=False)
+        monkeypatch.delenv("no_proxy", raising=False)
 
         client = DefaultAsyncHttpxClient()