As schools adopt more inclusive practices, educators increasingly collaborate and co-teach to meet the needs of diverse learners. Co-teaching has been found to have benefits for students across elementary and secondary grades. However, there is a need for teacher educators to provide more preservice training in collaboration and in co-teaching. This mixed method study describes the experience of 20 general education teacher candidates, or residents, using co-teaching models to differentiate instruction with their mentor teachers in high school math and science classrooms of a yearlong urban teacher residency programme. Data included surveys on co-teaching and resident evaluations of lessons co-taught with their mentors, and how these practices influence inclusion of children with special needs. Findings indicate some comfort and effectiveness at implementing co-teaching models in the residency. Implications for preparing preservice general educators using co-teaching models in residency are shared.