Deci and Ryan (2002) posit the importance of three sources of interpersonal support processes that when fostered authentically enhances psychological need fulfillment and well-being. Guided by Deci and Ryan’s (2002) contentions, the purpose of the study was to determine if interpersonal supports provided by exercise instructors was associated with well-being via the satisfaction of basic psychological needs in persons living with osteoporosis. Using a non-experimental research design, participants (N = 280) completed a self-report instrument at the mid-point of a 10 week structured OsteoFit exercise class. Results generally supported Deci and Ryan’s (2002) hypothesized sequence. Interpersonal supports demonstrated a pattern of small-to-moderate correlations with psychological need fulfillment (r12’s ranged from .37 to .47) and well-being (r12’s ranged from −.07 to .26). Multiple mediation analysis revealed that variance in psychological need satisfaction (R2 = 0.14 to 0.22) and markers of well-being (R2 = 0.03 to 0.32) was explained by the proposed model. This investigation provides support for the role of interpersonal supports in a clinical population where sustained and regular exercise is associated with physical and psychological health consequences. The importance of creating supportive environments within OsteoFit classes to optimize effects on well-being is highlighted.