Supporting agency can be complex and challenging, especially when teaching students with severe disabilities (i.e., students with intellectual disability, autism, and/or multiple disabilities who are eligible for their state's alternate assessment). In this article, we compare Bandura's model of agency with constructs from the severe disabilities literature (i.e., self-determination and social role valorization) to identify unique challenges for promoting agency with this population. In particular, we focus on how a common staffing pattern in special education--assigning one-to-one staff to work with students with severe disabilities--can unintentionally decrease opportunities for student agency. We describe peer support arrangements, an alternative support model that intentionally fades adult support in order to promote self-determined behavior and student agency. We highlight how this evidence demonstrates that despite unique challenges, it is possible to promote agency for students with severe disabilities through approaches such as peer support arrangements.