diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0b9ad284ab..2fc9be5e3e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -732,7 +732,7 @@ set(HOST_TARGET_TRIPLE "${HOST_TARGET_ARCH}-${HOST_TARGET_OS}")
 if(MSVC)
   set(ZIG_WASM2C_COMPILE_FLAGS "")
   set(ZIG1_COMPILE_FLAGS "/Os")
-  set(ZIG2_COMPILE_FLAGS "/O0")
+  set(ZIG2_COMPILE_FLAGS "/Od")
   set(ZIG2_LINK_FLAGS "/STACK:16777216")
 else()
   set(ZIG_WASM2C_COMPILE_FLAGS "-std=c99 -O2")