This paper reports on research that examines the use of acknowledging moves in the single-sex group discussions of 12-13-year-old girls and boys in their Key Stage 3 Design and Technology lessons. Within structural-functional models of discourse analysis, acknowledging moves are a discourse feature that perform the function of providing feedback to another speaker's utterance. Cullen (2002) has noted that little attention has been paid to the use of these moves in classroom interaction, arguing that this is a serious oversight as this part of the classroom exchange can perform important educational functions. The study of acknowledging moves has been even more neglected in the study of pupil group discussion, especially in relation to gender, and this paper aims to provide a contribution towards addressing this research gap. Employing techniques of functional discourse analysis, the findings of this study show that there are considerable differences in both the amounts and types of acknowledging moves used by the girls and boys in their respective group discussions. I suggest that, and attempt to illustrate how, these discoursal differences may contribute to our understanding of gender-differentiated attainment levels in Key Stage 3 Design and Technology.