This article concerns issues of classroom management in heterogeneous classrooms. Although research in the field of learning styles has yielded mixed results, there is a call for information about how they could be used to individualize instruction, especially in primary schools. This article is part of an ethnographic study aiming to examine teacher collaboration in a primary school and it draws strongly on field notes and on interviews with teachers. The intention was to discover how the two teachers in the classroom studied categorized pupils according to the learning styles model they had invented, and how the resulting groups were used for the purposes of classroom management. The study revealed that, first, learning styles seem to work as a grouping method and, second, that flexible grouping can diminish problematic situations traditionally related to heterogeneous classrooms. (Contains 1 table and 1 figure.)