diff --git a/lib/variables/variable.cpp b/lib/variables/variable.cpp
index 44cf5358..5ea0942a 100644
--- a/lib/variables/variable.cpp
+++ b/lib/variables/variable.cpp
@@ -54,6 +54,7 @@ void Variable::Save(obs_data_t *obj) const
 
 std::string Variable::Value(bool updateLastUsed) const
 {
+	std::lock_guard<std::mutex> lock(_mutex);
 	if (updateLastUsed) {
 		UpdateLastUsed();
 	}
@@ -73,6 +74,7 @@ std::optional<int> Variable::IntValue() const
 
 void Variable::SetValue(const std::string &value)
 {
+	std::lock_guard<std::mutex> lock(_mutex);
 	_previousValue = _value;
 	_value = value;
 
diff --git a/lib/variables/variable.hpp b/lib/variables/variable.hpp
index 4bdf1c91..1f45e71b 100644
--- a/lib/variables/variable.hpp
+++ b/lib/variables/variable.hpp
@@ -3,10 +3,11 @@
 #include "item-selection-helpers.hpp"
 #include "resizing-text-edit.hpp"
 
-#include <string>
-#include <optional>
-#include <QStringList>
+#include <mutex>
 #include <obs-data.h>
+#include <optional>
+#include <string>
+#include <QStringList>
 
 namespace advss {
 
@@ -52,6 +53,7 @@ private:
 	int _valueChangeCount = 0;
 	mutable std::chrono::high_resolution_clock::time_point _lastUsed;
 	mutable std::chrono::high_resolution_clock::time_point _lastChanged;
+	mutable std::mutex _mutex;
 
 	friend VariableSelection;
 	friend VariableSettingsDialog;