This study investigated the effects of collaborative group work skills training on pupil attainment in science. Twenty-four experimental classes were drawn from schools in rural and urban settings. Pupils in experimental classrooms engaged in general group work skills training and two structured group work activities in science. Attainment was assessed using the Performance Indicators in Primary Schools (PIPS) instrument. Significant gains in science attainment were observed in the experimental urban and rural classes. Significant changes in observed group work behaviours were observed in both urban and rural classes. Changes in group work behaviour were correlated to increased science attainment. The implications for practice, policy and future research are explored. (Contains 2 tables.)