Introduction: Peer support is a promising strategy for the reduction of diabetes-related health disparities; however, few studies describe the development of such strategies in enough detail to allow for replication. The objective of this article is to describe the development of a 1-year peer support intervention to improve diabetes self-management among African American adults with diabetes in Alabama's Black Belt. Methods: We used principles of intervention mapping, including literature review, interviews with key informants, and a discussion group with community health workers, to guide intervention development. Qualitative data were combined with behavioral constructs and principles of diabetes self-management to create a peer support intervention to be delivered by trained peer advisors. Feedback from a 1-month pilot was used to modify the training and intervention. Results: The resulting intervention includes a 2-day training for peer advisors, who were each paired with 3 to 6 clients. A oneon- one in-person needs assessment begins an intensive intervention phase conducted via telephone for 8 to 12 weeks, followed by a maintenance phase of at least once monthly contacts for the remainder of the intervention period. A peer support network and process measures collected monthly throughout the study supplement formal data collection points at baseline, 6 months, and 12 months. Discussion: Intervention mapping provided a useful framework for the development of culturally relevant diabetes peer support intervention for African Americans living in Alabama's Black Belt. The process described could be implemented by others in public health to develop or adapt programs suitable for their particular community or context.