© 2020, Annals of Family Medicine, Inc. All rights reserved. PURPOSE Cognitive behavioral therapy (CBT)–based programs delivered by trained community members could improve functioning and pain in individuals who lack access to such programs. We tested the effectiveness of a peer-delivered diabetes self-management program integrating CBT principles in improving physical activity, functional status, pain, quality of life (QOL), and health outcomes in individuals with diabetes and chronic pain. METHODS In this community-based, cluster-randomized controlled trial, intervention participants received a 3-month, peer-delivered, telephone-administered program. Attention control participants received a peer-delivered general health advice program. Outcomes were changes in functional status and pain (Western Ontario and McMaster Universities Osteoarthritis Index), QOL (Short Form 12), and physiologic measures (hemoglobin A1c, systolic blood pressure, body mass index); physical activity was the explanatory outcome. RESULTS Of 195 participants with follow-up data, 80% were women, 96% African Americans, 74% had annual income <$20,000, and 64% had high school education or less. At follow-up, compared with controls, intervention participants had greater improvement in functional status (–10 ± 13 vs –5 ± 18, P =.002), pain (–10.5 ± 19 vs –4.8 ± 21, P =.01), and QOL (4.8 ± 8.8 vs 3.8 ± 8.8, P =.001). Physiologic measures did not change significantly in either group. At 3 months, a greater proportion of intervention than control participants reported no pain or did other forms of exercise when pain prevented them from walking for exercise. CONCLUSION This peer-delivered CBT-based intervention improved functioning, pain, QOL, and self-reported physical activity despite pain in individuals with diabetes and chronic pain. Trained community members can deliver effective CBT-based interventions in rural and under-resourced communities.