Currently, many special education policymakers, researchers, and practitioners are questioning the efficacy of pull-out programs for students with disabilities and advocating service delivery in inclusive or general education settings at both the elementary and the secondary level. I investigated the implementation of a collaborative teaching model in a suburban high school to determine how this move toward inclusive education benefited teachers and students. Through examination of the "ups and downs" of a U.S. History teacher, I concluded that replicating and sustaining collaborative teaching can be difficult and complex and, without careful consideration of contextual variables, may not lead to improved outcomes for either teachers or students. Implications for research and practice are discussed.