diff --git a/setup.py b/setup.py
index 9f349b5564..80cfa5e475 100644
--- a/setup.py
+++ b/setup.py
@@ -167,7 +167,10 @@ def build_extension(self, ext):
                     cfg.upper(), os.path.join(extdir, "impactx")
                 ),
             ]
-            if sys.maxsize > 2**32:
+            generator_platform = os.environ.get("CMAKE_GENERATOR_PLATFORM")
+            if generator_platform:
+                cmake_args += ["-A", generator_platform]
+            elif sys.maxsize > 2**32:
                 cmake_args += ["-A", "x64"]
         else:
             cmake_args += ["-DCMAKE_BUILD_TYPE=" + cfg]