diff --git a/CMakeLists.txt b/CMakeLists.txt
index 303fcae..718ae88 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,15 +35,16 @@ ENDIF(BUILD_SHARED_LIBS)
 
 ADD_CUSTOM_TARGET(doc)
 
-FIND_PACKAGE(Doxygen)
-IF(DOXYGEN_FOUND)
-  ADD_CUSTOM_TARGET(doxygen
-    ${DOXYGEN_EXECUTABLE}
-    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    COMMENT "Doxygen ...")
-  ADD_DEPENDENCIES(doc doxygen)
-
-ENDIF(DOXYGEN_FOUND)
+IF (WIN32) # doxygen only have windows package in vcpkg now.
+   FIND_PACKAGE(Doxygen)
+   IF(DOXYGEN_FOUND)
+     ADD_CUSTOM_TARGET(doxygen
+       ${DOXYGEN_EXECUTABLE}
+       WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+       COMMENT "Doxygen ...")
+     ADD_DEPENDENCIES(doc doxygen)
+   ENDIF(DOXYGEN_FOUND)
+ENDIF()
 
 SUBDIRS(src)