Across many countries girls perform more unpaid work than boys. This article shows how time spent in unpaid household work by young women and girls contributes to the gender pay gap which is already evident by age 22. We analyse employment participation, type of employment and wages using five waves of the Young Lives longitudinal survey for Ethiopia, India, Peru and Vietnam. Longer hours in unpaid household work in adolescence positively predict later employment participation but have a scarring effect in negatively predicting job quality, that is a job with a private or public organization, and hourly earnings, particularly for women. Blinder-Oaxaca decompositions of the gender wage gap show young women’s penalty for past household work is due to longer hours of such work rather than a higher female penalty for a given amount of unpaid work.