With the increasing use of work teams in U.S. industry, understanding team members' collectivistic orientation toward group goals and activities is critical for developing cooperative and productive teams. Using the research on expectancy theory, self-efficacy, locus of control, and individualism–collectivism, collectivism is examined as both an individual difference variable and a group composition variable. One hundred and forty-eight individuals (comprising 33 groups) working on a complex and interdependent task comprised the research sample. Results indicated that individual difference variables of self-efficacy for teamwork, need for social approval, and positive past experience working in teams were related to self-report collectivism. Additionally, team collectivistic orientation was examined as a group composition variable and found to be related to cooperative team behaviors. In turn, these cooperative team behaviors acted as a mediator of the relationship between team collectivistic orientation and team performance. Results are discussed in terms of theory building and applied research. © 1997 John Wiley & Sons, Ltd.