Many mothers work in jobs with nonstandard schedules (i.e., schedules that involve work outside of the traditional 9-5, Monday through Friday schedule); this is particularly true for economically disadvantaged mothers. In the present article, we used longitudinal data from the Fragile Families and Child Wellbeing Survey (n = 2,367 mothers of children ages 3-5 years) to examine the associations between maternal nonstandard work and children's behavior problems, with a particular focus on mothers' night shift work. We employed 3 analytic strategies with various approaches to adjusting for observed and unobserved selection factors; these approaches provided an upper and lower bound on the true relationship between night shift work and children's behavior. Taken together, the results provide suggestive evidence for modest associations between exposure to maternal night shift work and higher levels of aggressive and anxious or depressed behavior in children compared with children whose mothers who are not working, those whose mothers work other types of nonstandard shifts, and, for aggressive behavior, those whose mothers work standard shifts.