OBJECTIVE: Appreciative Inquiry (AIn) is a strengths-based organizational framework to promote engagement and change. It has shown promise in graduate medical education settings, but how, why, and for whom AIn may drive educational outcomes is underexplored. This realist evaluation examines the causal relationships between contexts, mechanisms, and outcomes at a rheumatology fellowship program in a large tertiary care center that implemented a set of AIn-based interventions. We generate recommendations for leaders in rheumatology fellowship programs on the implementation of AIn-based interventions. METHODS: The realist evaluation was conducted in 3 phases. In phase 1, a scoping review informed the initial program theory. In phase 2, realist interviews were conducted to identify and refine causal relationships between contexts, mechanisms, and outcomes, yielding a final program theory. In phase 3, the final program theory was utilized to generate recommendations for implementation. RESULTS: The final program theory identified 15 contexts, 10 mechanisms, and 10 outcomes along with 43 context-mechanism-outcome configurations. Through analysis of the final program theory, 3 recommendations were generated: (1) programs must first create permission structures for critical self-reflection through strengths-based feedback, (2) programs must consistently and synergistically apply AIn principles at multiple levels, and (3) programs can sustain AIn-based interventions through the deliberate co-design of virtuous cycles. CONCLUSIONS: This realist evaluation has generated a theory on how AIn may be implemented into rheumatology fellowship programs to drive educational outcomes. Because of the intricate causal relationships, leaders are well-advised to tailor AIn-based interventions based on the context of their training programs.