diff --git a/src/symbols/symbols.hpp b/src/symbols/symbols.hpp
index 7a89144..9e25fc0 100644
--- a/src/symbols/symbols.hpp
+++ b/src/symbols/symbols.hpp
@@ -3,6 +3,7 @@
 
 #include <cpptrace/cpptrace.hpp>
 
+#include <functional>
 #include <string>
 #include <unordered_map>
 #include <utility>