Today's classrooms increasingly challenge teachers to address a diverse range of backgrounds, abilities, and learning needs. As teachers rise to the challenge, grouping can be a valuable instructional tool to address varying ability levels and learning needs within the classroom. At present, there is a good deal of support in the literature for heterogeneous grouping, in part as an effort to maintain high standards regardless of ability. However, as teachers know well, students enter the classroom at different levels across content areas and need varying forms of instruction to appropriately challenge them. Flexible grouping strategies can assist all teachers in meeting the needs of the students in the classroom. The goal of this "Focus On" is to move beyond a discussion of ability grouping and tracking by exploring the multitude of grouping strategies that teachers can use in their classrooms. The authors examine the various grouping patterns, summarizing the research-based evidence for each; address implementation questions, such as classroom management; and discuss the use of flexible grouping and adjustments to curriculum as necessary components. (Contains 77 resources and 5 web resources.)