One goal of a longitudinal study of stepfamilies, divorced maternal custody families, and nondivorced families was to assess the response of children to the experiences associated with stepfamily formation and to identify factors that may buffer children against adverse life experiences or make them more vulnerable to negative outcomes. Children's adjustment was measured at three time periods over 2.5 years. Composite measures of externalizing, internalizing, and competence were created from reports of mothers, fathers, teachers, and children from interviews and 24-Hour Behavior Checklists, as well as from observational measures based on a composite of global rating scales. The results showed that boys from divorced families exhibited fewer problems over time, as they continued to adjust to life in a single-parent household, whereas girls in divorced families exhibited more problems over time. Boys in remarried families exhibited high levels of problematic behavior throughout the course of the study, while girls in remarried families showed some improvement. Levels of competent behavior were highest for children from nondivorced homes, and lowest for children from remarried homes. Girls were viewed as more competent than boys throughout this age range. Analyses were conducted to examine which factors attenuate or exacerbate problems in adaptation, with a focus on externalizing disorders. (NB)