diff --git a/mesonbuild/cmake/toolchain.py b/mesonbuild/cmake/toolchain.py
index abf2cf6..477629e 100644
--- a/mesonbuild/cmake/toolchain.py
+++ b/mesonbuild/cmake/toolchain.py
@@ -204,6 +204,6 @@ class CMakeToolchain:
     @staticmethod
     def is_cmdline_option(compiler: 'Compiler', arg: str) -> bool:
         if compiler.get_argument_syntax() == 'msvc':
-            return arg.startswith('/')
+            return arg.startswith(('/','-'))
         else:
             return arg.startswith('-')