diff --git a/setup.py b/setup.py
index 32d94ae..920077d 100644
--- a/setup.py
+++ b/setup.py
@@ -12,6 +12,7 @@ import os.path
 import pathlib
 import platform
 import re
+import shlex
 import shutil
 import subprocess
 import sys
@@ -23,7 +24,7 @@ from setuptools.command.sdist import sdist
 
 CYTHON_DEPENDENCY = 'Cython~=3.0'
 MACHINE = platform.machine()
-MODULES_CFLAGS = [os.getenv('UVLOOP_OPT_CFLAGS', '-O2')]
+MODULES_CFLAGS = shlex.split(os.getenv('UVLOOP_OPT_CFLAGS', '-O2'))
 _ROOT = pathlib.Path(__file__).parent
 LIBUV_DIR = str(_ROOT / 'vendor' / 'libuv')
 LIBUV_BUILD_DIR = str(_ROOT / 'build' / 'libuv-{}'.format(MACHINE))