diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 11d14e4..0fa3e1e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -137,6 +137,21 @@ set_target_properties(
       1.1
 )
 
+if(USE_SYSTEM_RAPIDJSON)
+  find_package(RapidJSON CONFIG REQUIRED)
+  target_link_libraries(libopencc PRIVATE rapidjson)
+endif()
+
+if(USE_SYSTEM_TCLAP)
+  find_path(TCLAP_INCLUDE_DIRS "tclap/Arg.h")
+  target_include_directories(libopencc PUBLIC ${TCLAP_INCLUDE_DIRS})
+endif()
+
+if(USE_SYSTEM_DARTS)
+  find_path(DARTS_INCLUDE_DIRS "darts.h")
+  target_include_directories(libopencc PUBLIC ${DARTS_INCLUDE_DIRS})
+endif()
+
 # Installation
 
 install(