Emeryville, California's Fair Workweek Ordinance (FWO) aimed to reduce service workers' schedule unpredictability by requiring large retail and food service employers to provide advanced notice of schedules and to compensate workers for last-minute schedule changes. From ninety-six workers with young children (N = 78 in longitudinal analyses; 58 percent working in regulated businesses at baseline), this study gathered daily reports of work schedule unpredictability and worker and family well-being over three waves before and after FWO implementation. The FWO decreased working parents' schedule unpredictability and improved their well-being relative to those in similar jobs at unregulated establishments. The FWO also decreased parents' days worked while increasing hours per work day, leaving total hours roughly unchanged. Finally, parent well- being improved and declines in sleep difficulty were significant.