Residence hall residents indicated their attitudes about recycling and their perceptions of whether friends and family believed they should recycle at the beginning and toward the end of a semester. They also reported their recycling behavior at the end of the semester. Attitudes, but not subjective norms, predicted behavior, and participants became more similar to their fellow group members in attitudes and behavior over time. Attitudes and fellow group member behavior best predicted recycling, supporting the theory of reasoned action, dynamic social impact theory, and their integration.