diff --git a/tests/unit_tests/build_gen/test_arduino8266.py b/tests/unit_tests/build_gen/test_arduino8266.py
index 4f4c96d0d5..f76b4856c2 100644
--- a/tests/unit_tests/build_gen/test_arduino8266.py
+++ b/tests/unit_tests/build_gen/test_arduino8266.py
@@ -12,6 +12,7 @@ from __future__ import annotations
 
 from collections.abc import Generator
 import logging
+import os
 from pathlib import Path
 from unittest.mock import MagicMock, patch
 
@@ -637,7 +638,10 @@ def test_project_flags_requotes_lexed_defines() -> None:
     )
     # shlex folds the quotes (as PIO's ParseFlags does); _shell_token
     # re-quotes the spaced token so the shell passes one argv element
-    assert compile_flags == ['"-DGREETING=hello world"']
+    expected = (
+        '"-DGREETING=hello world"' if os.name == "nt" else "'-DGREETING=hello world'"
+    )
+    assert compile_flags == [expected]
 
 
 def test_write_project_empty_core_raises(tmp_path: Path) -> None: