This study applied expectancy theory to integrate the numerous and disparate explanations that researchers and educators have proposed to account for teacher resistance to implementing cooperative learning as an educational innovation. The cooperative learning implementation questionnaire (CLIQ) contained 48 items grouped under three broad motivational categories: perceived value of the innovation, expectancy of success, and perceived cost. These items accounted for 42.3% of the total variance in self-reported use of cooperative learning among 933 teachers. Expectancy of success issues were most important in differentiating users and non-users, suggesting that increased emphasis on professional development should be used to enhance teachers' beliefs that they can succeed in implementing an innovation in their own context. This may require both follow-up support and adaptation of the innovation.