• adolescence;
  • child outcomes;
  • mother–child relations;
  • time diary methods

Although intensive mothering ideology underscores the irreplaceable nature of mothers' time for children's optimal development, empirical testing of this assumption is scant. Using time diary and survey data from the Panel Study of Income Dynamics Child Development Supplement, the authors examined how the amount of time mothers spent with children ages 3–11 (N = 1,605) and adolescents 12–18 (N = 778) related to offspring behavioral, emotional, and academic outcomes and adolescent risky behavior. Both time mothers spent engaged with and accessible to offspring were assessed. In childhood and adolescence, the amount of maternal time did not matter for offspring behaviors, emotions, or academics, whereas social status factors were important. For adolescents, more engaged maternal time was related to fewer delinquent behaviors, and engaged time with parents together was related to better outcomes. Overall, the amount of mothers' time mattered in nuanced ways, and, unexpectedly, only in adolescence.