The aim of this small-scale study was to investigate the effect of pupil-generated ground rules on peer group learning in a class of 9-year-old boys. The study examined the type of talk used by participants working in a group before the introduction of ground rules and compared this with that used after the introduction of ground rules. It was predicted that rules would change the quality and quantity of talk in particular the use of "exploratory talk". This hypothesis was supported by the results from both quantitative and qualitative analyses. The results provided additional evidence for Dawes et al.'s (1992) contention that pupil-generated ground rules enhance peer group learning. However, such a small-scale study was not without limitations and the results have to be treated cautiously before firmer conclusions can be made. The implications of the findings are discussed in relation to existing theory and suggestions for subsequent research and professional practice are made. (Contains 1 table.)