diff --git a/CI/before_script.msvc.sh b/CI/before_script.msvc.sh
index ff8ec1a11c..ec5e9a7da8 100644
--- a/CI/before_script.msvc.sh
+++ b/CI/before_script.msvc.sh
@@ -530,6 +530,9 @@ if ! [ -z $USE_CCACHE ]; then
 	add_cmake_opts "-DCMAKE_C_COMPILER_LAUNCHER=ccache  -DCMAKE_CXX_COMPILER_LAUNCHER=ccache"
 fi
 
+# turn on LTO by default
+add_cmake_opts "-DOPENMW_LTO_BUILD=True"
+
 if ! [ -z "$USE_WERROR" ]; then
   add_cmake_opts "-DOPENMW_MSVC_WERROR=ON"
 fi