diff --git a/Libraries/LibJS/Interpreter.cpp b/Libraries/LibJS/Interpreter.cpp
index d79b57f2db..22f8489d87 100644
--- a/Libraries/LibJS/Interpreter.cpp
+++ b/Libraries/LibJS/Interpreter.cpp
@@ -92,6 +92,7 @@ Value Interpreter::run(const Statement& statement, ArgumentVector arguments, Sco
 void Interpreter::enter_scope(const ScopeNode& scope_node, ArgumentVector arguments, ScopeType scope_type)
 {
     HashMap<FlyString, Variable> scope_variables_with_declaration_kind;
+    scope_variables_with_declaration_kind.ensure_capacity(16);
 
     for (auto& declaration : scope_node.variables()) {
         for (auto& declarator : declaration.declarations()) {