The current study evaluates the interaction between mastery, depression, and psychological barriers to care among older adults in a primary care setting, including the longitudinal effects of anticipated stigma and mastery on depressive symptoms. The sample was composed of 70 depressed older adults (age ≥ 60) who were newly recommended antidepressant treatment by their physicians. This cohort is part of a larger study examining the usefulness of the Treatment Initiation and Participation program to improve medication adherence. Anticipated stigma significantly predicted greater depression among older adults with low mastery, but not among those with high mastery. Mastery was found to moderate the relationship between anticipated stigma and depressive symptoms among older adults. Increased mastery over 28 weeks was also associated with greater reductions in depressive symptoms at follow-up, controlling for antidepressant strength and adherence. Bolstering older adults' sense of mastery in treatment could provide a source of resilience for older adults facing depression.