This paper reports on a study into the motives underlying the formation of a weekly English discussion group organized by mainland Chinese research students in Hong Kong as a strategic effort to improve their English. Adopting a sociocultural approach, we compared our interpretations of semi-structured interview transcripts and other data, focusing in particular the participants' strong English learning motivation. It was found that their motives were very complex and could best be explained by the notion of investment (Norton, 1995). These motives also became the primary forces that transformed the weekly event from a learning event into a variety of activities that moved beyond improving their English speaking skills for individual participants. The paper argues that a more sociocultural or sociopolitical perspective on learning strategy should be adopted to deepen our understanding of language learners' strategic learning behaviour. Copyright © 2008 John Benjamins Publishing Company.