Children frequently must adapt to changes in their environments, such as school transitions. The different types of social support from different sources were examined here so as to determine the processes by which such support mediates the stress of school transitions. Students' perceptions of the types or amount of support they received from parents, friends, and teachers, and whether or not different types of support mediated school transition in different domains, were highlighted. Sixth-grade students (N=95) were followed as they made the transition and adjustment to junior high school. Students completed a series of questionnaires evaluating the strength and types of social support they received from three major sources: peers, parents, and teachers. The types of support examined included informational, tangible, emotional, and social companionship support. Results indicate that parents provided more tangible support than teachers and friends and more emotional support than teachers. Informational support from friends best predicted social adjustment to seventh grade which indicates that having friends who provide help coping with problems is an important predictor of group integration and personal intimacy. Findings indicate ways in which social support mediates stress in early adolescence. Contains 12 references. (RJM)