This study was aimed at investigating the impact of cooperative learning on the motivation of tertiary English learners. Participants were from two randomly assigned classes at a university in the north of China. A pre-test-post-test control group design was employed to compare the impact of the cooperative learning approach with that of traditional whole-class instruction on six aspects of learning motivation: intrinsic motivation, integrated regulation, identified regulation, introjected regulation, external regulation and amotivation. Findings suggested significant differences in favour of cooperative learning in improving intrinsic motivation, but no differences were found on other aspects of motivation.