diff --git a/CMakeLists.txt b/CMakeLists.txt
index d3ab20d42..22461fbdd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -217,8 +217,12 @@ set(FCITX_INSTALL_LOCALEDIR ${CMAKE_INSTALL_FULL_LOCALEDIR})
 set(FCITX_INSTALL_ADDONDIR "${CMAKE_INSTALL_FULL_LIBDIR}/fcitx5")
 set(FCITX_INSTALL_CMAKECONFIG_DIR "${CMAKE_INSTALL_FULL_LIBDIR}/cmake")
 set(FCITX_INSTALL_MODULE_HEADER_DIR "${CMAKE_INSTALL_FULL_INCLUDEDIR}/Fcitx5/Module/fcitx-module")
-# TODO mac/win
-set(FCITX_LIBRARY_SUFFIX ".so")
+
+if (WIN32)
+    set(FCITX_LIBRARY_SUFFIX ".dll")
+else()
+    set(FCITX_LIBRARY_SUFFIX ".so")
+endif()
 
 check_function_exists(pipe2 HAVE_PIPE2)