diff --git a/include/CommonLib/ChunkEntities.hpp b/include/CommonLib/ChunkEntities.hpp
index b6e9794..52336fa 100644
--- a/include/CommonLib/ChunkEntities.hpp
+++ b/include/CommonLib/ChunkEntities.hpp
@@ -78,6 +78,7 @@ namespace tsom
 			NazaraSlot(ChunkContainer, OnChunkUpdated, m_onChunkUpdated);
 			NazaraSlot(Nz::Node, OnNodeInvalidation, m_onParentNodeInvalidated);
 
+			std::mutex m_invalidatedChunkMutex;
 			entt::handle m_parentEntity;
 			tsl::hopscotch_map<ChunkIndices, DirectionMask> m_invalidatedChunks;
 			tsl::hopscotch_map<ChunkIndices, std::shared_ptr<UpdateJob>> m_updateJobs;
diff --git a/src/CommonLib/ChunkEntities.cpp b/src/CommonLib/ChunkEntities.cpp
index 8784d41..db1b734 100644
--- a/src/CommonLib/ChunkEntities.cpp
+++ b/src/CommonLib/ChunkEntities.cpp
@@ -42,6 +42,8 @@ namespace tsom
 
 		m_onChunkUpdated.Connect(chunkContainer.OnChunkUpdated, [this](ChunkContainer* /*emitter*/, Chunk* chunk, DirectionMask neighborMask)
 		{
+			// Chunks can be updated in parallel (e.g. planet generation)
+			std::lock_guard lock(m_invalidatedChunkMutex);
 			m_invalidatedChunks[chunk->GetIndices()] |= neighborMask;
 		});
 	}