diff --git a/runtime/mem/ecma_reference_processor.cpp b/runtime/mem/ecma_reference_processor.cpp
index 8762f45d4dd945ac3dc9f193dc7cacc019d7dd6b..9332406fbf5a230483803f5af198470cef986454 100644
--- a/runtime/mem/ecma_reference_processor.cpp
+++ b/runtime/mem/ecma_reference_processor.cpp
@@ -109,6 +109,7 @@ void EcmaReferenceProcessor::HandleReference([[maybe_unused]] GC *gc, [[maybe_un
                                              [[maybe_unused]] const BaseClass *base_class, const ObjectHeader *object,
                                              [[maybe_unused]] const ReferenceProcessPredicateT &pred)
 {
+    os::memory::LockHolder lock(weak_ref_lock_);
     dyn_weak_references_.insert(const_cast<ObjectHeader *>(object));
 }
 
@@ -117,6 +118,7 @@ void EcmaReferenceProcessor::ProcessReferences([[maybe_unused]] bool concurrent,
                                                [[maybe_unused]] GCPhase gc_phase,
                                                [[maybe_unused]] const mem::GC::ReferenceClearPredicateT &pred)
 {
+    os::memory::LockHolder lock(weak_ref_lock_);
     panda::ecmascript::JSThread *thread = vm_->GetAssociatedJSThread();
     while (!dyn_weak_references_.empty()) {
         ObjectHeader *reference = *dyn_weak_references_.begin();
diff --git a/runtime/mem/ecma_reference_processor.h b/runtime/mem/ecma_reference_processor.h
index ccda217374df2cd1ad4e57a77dc57d55e59f8c80..87210af03cc6ae996a9d6ceb20d9633b5126a529 100644
--- a/runtime/mem/ecma_reference_processor.h
+++ b/runtime/mem/ecma_reference_processor.h
@@ -66,11 +66,13 @@ public:
 
     size_t GetReferenceQueueSize() const override
     {
+        os::memory::LockHolder lock(weak_ref_lock_);
         return dyn_weak_references_.size();
     }
 
 private:
-    PandaUnorderedSet<ObjectHeader *> dyn_weak_references_;
+    mutable os::memory::Mutex weak_ref_lock_;
+    PandaUnorderedSet<ObjectHeader *> dyn_weak_references_ GUARDED_BY(weak_ref_lock_);
     panda::ecmascript::EcmaVM *vm_;
     GC *gc_;
 };