diff --git a/setup.py b/setup.py
index fdda237e..2c4e8396 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,7 @@
 if sys.platform.startswith("darwin"):
     print("Running on macOS")
     platform_cxx_flags = ["-std=c++20", "-stdlib=libc++", "-mmacosx-version-min=10.15"]
-    os.environ["MACOSX_DEPLOYMENT_TARGET"] = 10.15
+    os.environ["MACOSX_DEPLOYMENT_TARGET"] = "10.15"
 
 elif sys.platform.startswith("linux"):
     print("Running on Linux")