This document summarizes research on collaboration between teachers and discusses various co-teaching models. It begins by outlining findings from McKinsey reports that collaborative teaching practices improve student outcomes by making instruction more focused on student learning. The document then describes five common co-teaching models: one teach, one support; parallel groups; station teaching; one large group, one small group; and teaming. Each model is defined and examples are provided. Overall, the document advocates for co-planning and co-teaching to better meet student needs through differentiated instruction.