diff --git a/SPIRV/CMakeLists.txt b/SPIRV/CMakeLists.txt
index a80e74ed..8a15f00d 100644
--- a/SPIRV/CMakeLists.txt
+++ b/SPIRV/CMakeLists.txt
@@ -106,7 +106,7 @@ if(ENABLE_OPT)
     target_link_libraries(SPIRV PRIVATE MachineIndependent SPIRV-Tools-opt)
     target_include_directories(SPIRV PUBLIC
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../External>
-        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/External>)
+        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/>)
 else()
     target_link_libraries(SPIRV PRIVATE MachineIndependent)
 endif()
diff --git a/StandAlone/CMakeLists.txt b/StandAlone/CMakeLists.txt
index ad88442c..db2ca5ff 100644
--- a/StandAlone/CMakeLists.txt
+++ b/StandAlone/CMakeLists.txt
@@ -69,7 +69,7 @@ endif()
 target_link_libraries(glslang-standalone ${LIBRARIES})
 target_include_directories(glslang-standalone PUBLIC
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../External>
-    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/External>)
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
 
 if(ENABLE_OPT)
     target_include_directories(glslang-standalone