For married patients, chronic illness management often includes involvement of their spouses. We examined expectations regarding spouse involvement in the health of a partner with type 2 diabetes (N = 139 couples) from the perspectives of the patient and spouse. Partners' dyadic expectations and spouses' gender were posited to moderate spouses' diet-related control and patients' diet adherence. Among male patients, when both partners shared an expectation for spouse involvement greater diet-related spouse control was associated with better diet adherence of patients. In contrast, when expectations for spouse involvement were not shared, greater spouse control by wives was associated with poorer diet adherence. Dyadic expectations for spouse involvement did not moderate the association between spouse control and diet adherence among female patients. Findings suggest that shared expectations for spouse involvement can facilitate spouses' attempts to improve patients' dietary adherence, especially among male patients and their wives. (Contains 4 tables and 2 figures.)