Two studies were conducted to investigate the effects of cooperative learning on second-graders' motivation and learning from text. In Study 1, students (n = 160) in cooperative learning groups were compared with their counterparts (n = 107) in traditional instruction groups. The results revealed a statistically significant difference between the two groups, with more favourable perceptions of teachers' instructional practices and better reading comprehension in the instructional intervention groups than in the traditional instruction groups. In Study 2, 51 second-graders participated in the instructional intervention programme. The results showed that students' positive cooperative behaviour and attitudes were related to their motivation and reading comprehension. When students perceived that their peers were willing to help each other and were committed to the group, they tended to be more motivated and performed better in reading comprehension. [Copyright of Educational Psychology is the property of Routledge. Full article may be available at the publisher's website: http://dx.doi.org/10.1080/01443410701880159]