Abstract: We show that aging has boosted regional fiscal multipliers in the Euro Area, with labor market institutions driving substantial cross-regional heterogeneity. Multipliers are highest in regions with age-segmented dual labor markets, where aging increases nominal wage rigidity by reducing the share of young workers on flexible contracts, and in regions with generous unemployment benefits, which stabilize the incomes of credit-constrained young households in the aftermath of fiscal shocks. By contrast, in weakly segmented, low-benefit regions, aging reduces multipliers. A calibrated multi-region New Keynesian model rationalizes these patterns: aging raises multipliers under euro-area institutions but lowers them in U.S.-type settings where the amplification of fiscal shocks through highly responsive, credit-constrained young households dominates.