diff --git a/src/libslic3r/SLAPrint.cpp b/src/libslic3r/SLAPrint.cpp
index 52a4146bc..9fbf6aa8c 100644
--- a/src/libslic3r/SLAPrint.cpp
+++ b/src/libslic3r/SLAPrint.cpp
@@ -2,6 +2,8 @@
 #include "SLA/SLASupportTree.hpp"
 #include "SLA/SLABasePool.hpp"
 
+#include <unordered_set>
+
 #include <tbb/parallel_for.h>
 #include <boost/log/trivial.hpp>