Previous research suggested that social support, belongingness and mastery goals were related to the quality of cooperative learning (CL). In this in-depth study we explored how to differentiate between four effective CL teams and four ineffective CL teams, in terms of students' goals and perceptions of instructional conditions. Apart from the earlier mentioned goals we found students' preference for social responsibility, learning for a certificate and entertainment goals to be salient in the CL setting. Mastery and social responsibility goals were prevalent in effective teams, while learning for a certificate and entertainment goals were prevalent in ineffective teams. Moreover, the type of task, group composition and teacher support were mentioned as reasons for effective or ineffective CL.