diff --git a/build/cmake/lib/xml/CMakeLists.txt b/build/cmake/lib/xml/CMakeLists.txt
index d0c94d8dee..3afb4dccbd 100644
--- a/build/cmake/lib/xml/CMakeLists.txt
+++ b/build/cmake/lib/xml/CMakeLists.txt
@@ -12,7 +12,7 @@ include(../../source_groups.cmake)
 if(wxUSE_EXPAT STREQUAL "builtin")
     ExternalProject_Add(wxexpat
         DOWNLOAD_COMMAND ""
-        SOURCE_DIR ${wxSOURCE_DIR}/src/expat
+        SOURCE_DIR ${wxSOURCE_DIR}/src/expat/expat
         CMAKE_ARGS
             -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
             -DBUILD_tools=OFF