Co-teaching can be defined with a multitude of formats in a variety of educational settings. Its underlying concept is that at least two professionals collaborate during their instruction and strengthen their delivery, resulting in improved student outcomes. Partnerships that can be deemed as co-teaching could include pairing various combinations of university instructors, teachers of English-language learners, special education service providers, and student teachers but the following review of co-teaching targets the special education service model. In the preschool through high school setting, the continuing trend toward greater inclusion of students with disabilities means that all teachers are faced with teaching their content to increasingly diverse students. A popular service used to accomplish inclusive practices from preschool to high school is co-teaching. Co-teaching is a service by which students with disabilities and their teachers collaborate together for the purpose of providing students with and without disabilities access to the general education curriculum with specially designed instruction. Co-teaching usually occurs for a designated portion of the instructional day. By carefully planning together, co-teaching pairs provide more intense instruction to the entire class based on the general education content and the learning goals for students with disabilities. While instructing together, both teachers often form smaller instructional groups for more individualized lessons. The co-teachers use their assessment data to inform future instruction within the inclusive classroom. By implementing the effective co-teaching practices of shared planning, instructing, and assessing, teachers become equal partners for the benefit of all students.