diff --git a/src/storm/storage/jani/ParallelComposition.cpp b/src/storm/storage/jani/ParallelComposition.cpp
index d81db1d91..0d439e0ce 100644
--- a/src/storm/storage/jani/ParallelComposition.cpp
+++ b/src/storm/storage/jani/ParallelComposition.cpp
@@ -116,7 +116,7 @@ namespace storm {
             return !(vector1 == vector2);
         }
         
-        bool SynchronizationVectorLexicographicalLess::operator()(SynchronizationVector const& vector1, SynchronizationVector const& vector2) {
+        bool SynchronizationVectorLexicographicalLess::operator()(SynchronizationVector const& vector1, SynchronizationVector const& vector2) const {
             STORM_LOG_THROW(vector1.size() == vector2.size(), storm::exceptions::WrongFormatException, "Cannot compare synchronization vectors of different size.");
             for (uint64_t i = 0; i < vector1.size(); ++i) {
                 if (vector1.getInput(i) < vector2.getInput(i)) {
diff --git a/src/storm/storage/jani/ParallelComposition.h b/src/storm/storage/jani/ParallelComposition.h
index c3d41717c..381ace5f8 100644
--- a/src/storm/storage/jani/ParallelComposition.h
+++ b/src/storm/storage/jani/ParallelComposition.h
@@ -62,7 +62,7 @@ namespace storm {
         bool operator!=(SynchronizationVector const& vector1, SynchronizationVector const& vector2);
         
         struct SynchronizationVectorLexicographicalLess {
-            bool operator()(SynchronizationVector const& vector1, SynchronizationVector const& vector2);
+            bool operator()(SynchronizationVector const& vector1, SynchronizationVector const& vector2) const;
         };
         
         std::ostream& operator<<(std::ostream& stream, SynchronizationVector const& synchronizationVector);