We document that employee bankruptcy costs affect corporate capital structure decisions via their impact on the bargaining power of labor unions. We employ difference-in-differences and triple-difference research designs surrounding a major bankruptcy reform that increased personal bankruptcy costs. Our results suggest that, on average, this reform reduced unions’ bargaining power, resulting in a decrease in the financial leverage of unionized firms relative to nonunionized firms. Our results provide new evidence for a relatively unexplored determinant of capital structure—personal bankruptcy costs.