diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5d918f2b14..fbc34f8051 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,10 +10,14 @@ if(NOT CMAKE_INSTALL_PREFIX)
       "Directory to install zig to" FORCE)
 endif()
 
+set(CMAKE_USER_MAKE_RULES_OVERRIDE
+   ${CMAKE_CURRENT_SOURCE_DIR}/cmake/c_flag_overrides.cmake)
+set(CMAKE_USER_MAKE_RULES_OVERRIDE_CXX
+   ${CMAKE_CURRENT_SOURCE_DIR}/cmake/cxx_flag_overrides.cmake)
+
 project(zig C CXX)
 set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
 
-
 set(ZIG_VERSION_MAJOR 0)
 set(ZIG_VERSION_MINOR 5)
 set(ZIG_VERSION_PATCH 0)
diff --git a/cmake/c_flag_overrides.cmake b/cmake/c_flag_overrides.cmake
new file mode 100644
index 0000000000..0eed5308ba
--- /dev/null
+++ b/cmake/c_flag_overrides.cmake
@@ -0,0 +1,13 @@
+if(MSVC)
+    set(CMAKE_C_FLAGS_DEBUG_INIT
+        "/D_DEBUG /MTd /Zi /Ob0 /Od /RTC1")
+
+    set(CMAKE_C_FLAGS_MINSIZEREL_INIT
+        "/MT /O1 /Ob1 /D NDEBUG")
+
+    set(CMAKE_C_FLAGS_RELEASE_INIT
+        "/MT /O2 /Ob2 /D NDEBUG")
+
+    set(CMAKE_C_FLAGS_RELWITHDEBINFO_INIT
+        "/MT /Zi /O2 /Ob1 /D NDEBUG")
+endif()
diff --git a/cmake/cxx_flag_overrides.cmake b/cmake/cxx_flag_overrides.cmake
new file mode 100644
index 0000000000..82fb7b39d0
--- /dev/null
+++ b/cmake/cxx_flag_overrides.cmake
@@ -0,0 +1,13 @@
+if(MSVC)
+    set(CMAKE_CXX_FLAGS_DEBUG_INIT
+        "/D_DEBUG /MTd /Zi /Ob0 /Od /RTC1")
+
+    set(CMAKE_CXX_FLAGS_MINSIZEREL_INIT
+        "/MT /O1 /Ob1 /D NDEBUG")
+
+    set(CMAKE_CXX_FLAGS_RELEASE_INIT
+        "/MT /O2 /Ob2 /D NDEBUG")
+
+    set(CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT
+        "/MT /Zi /O2 /Ob1 /D NDEBUG")
+endif()