Group work is used in physical education (PE) to encourage student-directed, collaborative learning. Aligned with this aim, group work is expected to shift some power from teacher to students and enable students to make decisions and co-construct meaning on their own. There are, however, very few investigations focusing on power in group work situations in PE, with most research focusing on learning and content. Assumptions about the nature of power and its mechanisms have been largely implicit. The purpose of this paper was consequently to explore power relations in PE group work. To do this, we have drawn primarily on observational data of three groups working together to choreograph a dance performance in a Swedish PE lesson. A small amount of pre- and post-lesson interview material is used as a complementary data source. Michel Foucault's notion of power as action-on-action is used to identify different types of power relations in this group work. Four specific kinds of relations are presented concerning: (1) the students' task; (2) other cultures; (3) gender; and (4) interactions with one another. These relations suggest that power relations are not simply created locally between group members, nor are power relations only a function of the members' proficiency in the task. In these respects, the results encourage a reconsideration of learning in group work and open up new avenues for further research. The paper is concluded with practical considerations that relate to common assumptions about student power, teacher authority and the potential benefit of ambiguous tasks in group work.