Disparities in cancer survivorship are persistent and pervasive. Obesity, medical comorbidities, second primary cancers, poor quality of life and compromised physical functioning, disproportionately affect African American (AA) cancer survivors. There is strong evidence that physical activity (PA) has the potential to eliminate these disparities. Yet, insufficient PA is more prevalent among AA cancer survivors and 76% do not meet PA guidelines. Efforts to increase PA longer term in cancer survivors have been modestly successful. The extant literature and our own preliminary data in cancer survivors shows that PA adoption is often followed by an attenuation of PA over time. These findings have led to a recent shift in thinking, specifically that the social cognitive theory constructs (e.g., self-efficacy), important for PA adoption play less of a role in PA maintenance. Additional theoretical constructs (i.e., habit and identity) may be the key constructs necessary for long term behavior change. Conceivably, lack of success in promoting PA maintenance may also be due to few studies examining how well health behavior change interventions work in the broader societal context. For example, for AAs, discrimination is a potent social determinant of health. Discrimination is prevalent (reported by 82% of AA breast cancer survivors), disproportionate (AAs are more likely to report discrimination-related stress compared to other racial and ethnic groups), and stressful (stress, in general, impedes PA). Despite this evidence, the effect of discrimination on PA intervention outcomes is unknown. Thus, to advance PA maintenance science with a focus on a vulnerable population, we propose testing two potentially translatable PA maintenance promotion interventions (Short Message Service [SMS] and peer coach) in 260 physically inactive AA women cancer survivors using a rigorous, randomized 2 x 2 factorial experimental design. Survivors will complete a 3-month PA adoption phase (i.e., efficacious theory-based PA behavior change program) prior to randomization to a PA maintenance promotion intervention or usual care. Our 6-month SMS and peer coach PA maintenance promotion interventions will be guided by the Multi-Process Action Control (M-PAC) framework which includes constructs which are understudied in cancer survivors yet hypothesized to be important for PA maintenance (e.g., habit, identity). Assessments will occur at baseline (pre-PA adoption), 3 months (post-PA adoption; immediately prior to randomization), 9 months, and 15 months. Our specific aims are: 1) Determine effects of both PA maintenance interventions (SMS, peer coach) compared to usual care on PA maintenance (i.e., main effects and if either intervention effects differ in the presence of the other); 2) Identify theory-based mediators of PA maintenance; and 3) Determine if discrimination moderates intervention effects on PA maintenance. The project will generate new knowledge about the mechanisms un...