diff --git a/@ensemble/useVariables.m b/@ensemble/useVariables.m
index efafcfb3..4a23fb16 100644
--- a/@ensemble/useVariables.m
+++ b/@ensemble/useVariables.m
@@ -23,7 +23,7 @@
 else
     obj.stateVector.checkVariables(varNames);
     varNames = string(varNames);
-    varNames = unique(varNames(:));
+    varNames = unique(varNames(:), 'stable');
 end
 obj.variables = varNames;