diff --git a/lsplant/src/main/jni/include/lsplant.hpp b/lsplant/src/main/jni/include/lsplant.hpp
index 3ea2ca9..7542722 100644
--- a/lsplant/src/main/jni/include/lsplant.hpp
+++ b/lsplant/src/main/jni/include/lsplant.hpp
@@ -3,6 +3,7 @@
 #include <jni.h>
 
 #include <string_view>
+#include <functional>
 
 /// \namespace lsplant
 namespace lsplant {