diff --git a/Lib/distutils/command/bdist_wininst.py b/Lib/distutils/command/bdist_wininst.py
index fde5675..15434c3 100644
--- a/Lib/distutils/command/bdist_wininst.py
+++ b/Lib/distutils/command/bdist_wininst.py
@@ -55,6 +55,9 @@ class bdist_wininst(Command):
     boolean_options = ['keep-temp', 'no-target-compile', 'no-target-optimize',
                        'skip-build']
 
+    # bpo-10945: bdist_wininst requires mbcs encoding only available on Windows
+    _unsupported = (sys.platform != "win32")
+
     def initialize_options(self):
         self.bdist_dir = None
         self.plat_name = None