The general purpose of this investigation was to examine the relationship of group cohesion to individual adherence to physical activity. Two independent studies were conducted using present and former participants from organized sport programs, physical recreation programs, and physical exercise programs. The purpose of Study 1 was to determine if cohesiveness was related to adherence behavior in organized sport and exercise class settings. Study 2 explored the relationship of individual perceptions of group cohesion to absenteeism and lateness by summer recreation sport participants. The results from the two studies supported the conclusion that group cohesiveness is related to individual adherence behavior. This conclusion was supported across different group types including fitness classes, recreational team sports, and elite team sports. However, both the form and number of aspects of cohesion that were related to adherence were moderated by type of group. This underscores the necessity of conducting more comparative group research in future investigations.