Recent research suggests that wages below legally established minimum wages are surprisingly prevalent. This column reviews ‘wage theft’ in the US and its impact on the wage gains workers might otherwise enjoy. Most firms comply with increases in the minimum wage, especially when they have time to plan for the increase, but evasion and avoidance are also qualitatively important features of the low-wage labour market. Young African American workers experience the largest erosion of their potential wage gains following a minimum wage increase. Whether greater enforcement would improve the welfare of low-wage workers, however, remains an open question.