This study examined the effects of belongingness and synchronicity on cooperative learning. 171 students participated in constructive controversy discussions either face-to-face, synchronously online, or asynchronously online. They also received manipulations of belongingness (acceptance, mild rejection, control). Results showed that initial belongingness had positive effects on cooperation, motivation and technology perceptions. However, belongingness did not fully offset the negative effects of asynchronous discussions, which had poorer outcomes than face-to-face or synchronous discussions. The findings suggest belongingness is important but synchronicity also significantly impacts cooperative learning.