diff --git a/esphome/platformio_api.py b/esphome/platformio_api.py
index fa88776acf..81ff01306a 100644
--- a/esphome/platformio_api.py
+++ b/esphome/platformio_api.py
@@ -12,37 +12,6 @@ from esphome.util import FlashImage, run_external_process
 _LOGGER = logging.getLogger(__name__)
 
 
-def _strip_win_long_path_prefix(path: str) -> str:
-    r"""Strip the Windows extended-length path prefix from ``path``.
-
-    Handles both forms documented at
-    https://learn.microsoft.com/windows/win32/fileio/naming-a-file:
-
-    * ``\\?\C:\path\to\file`` -> ``C:\path\to\file``
-    * ``\\?\UNC\server\share\path`` -> ``\\server\share\path``
-
-    The NSIS-installed ``esphome.exe`` launcher on Windows starts Python with
-    ``sys.executable`` already prefixed with ``\\?\``. That prefix propagates
-    into PlatformIO's ``$PYTHONEXE`` (PlatformIO reads ``PYTHONEXEPATH`` from
-    the environment, falling back to ``os.path.normpath(sys.executable)``)
-    and ends up baked into SCons-emitted command lines for build steps such
-    as the esp8266 ``elf2bin`` invocation. ``cmd.exe`` does not understand
-    the ``\\?\`` prefix, so the build fails with
-    "The system cannot find the path specified." Stripping the prefix early
-    keeps the path shell-quotable.
-
-    No-op on non-Windows platforms.
-    """
-    if sys.platform != "win32":
-        return path
-    if path.startswith("\\\\?\\UNC\\"):
-        # \\?\UNC\server\share\... -> \\server\share\...
-        return "\\\\" + path[len("\\\\?\\UNC\\") :]
-    if path.startswith("\\\\?\\"):
-        return path[len("\\\\?\\") :]
-    return path
-
-
 def _strip_win_long_path_prefix(path: str) -> str:
     r"""Strip the Windows extended-length path prefix from ``path``.