The autonomous and controlled motivations underpinning goal pursuit directly impact physical activity and mental well-being and are important for healthy behavior adherence. Psychological variables can also affect physical activity and mental well-being. This study tested the association between goal motives, psychological variables, physical activity, and mental well-being using structural equation modelling. Adults (N = 323;Mage =32.46 +/- 13.12 y) completed a cross-sectional survey measuring goal motives, motivation, affective experiences, self-efficacy, physical activity, and mental well-being. Our analysis showed support for the proposed model fit: (chi 2(6) = 14.16, p = .028, RMSEA = .07, CFI = .99, TLI = .97). In contrast to controlled goal motives, autonomous goal motives were positively related to the psychological variables associated with physical activity and mental well-being. Motivation and affective experiences were positively associated with physical activity. Self-efficacy was positively associated with mental well-being. Intricacies of the associations between goal motives, psychological variables, physical activity, and mental well-being are discussed.