INTRO: Substance use and associated problems often return following treatment for substance use disorder (SUD), which disproportionally impact Black/African American (AA) individuals. Social support and spiritual well-being are sources of recovery capital identified as particularly important among Black/AA adults. Social support and spiritual well-being are also posited mechanisms in 12-step; thus, this study tested the effects of social support and spiritual well-being on substance use outcomes over time, distinct from 12-step involvement, among Black/AA adults post-SUD treatment. The study hypothesized that social support and spiritual well-being would demonstrate significant interactions with time, respectively, on substance use frequency and substance use consequences, above the effect of 12-step involvement. METHOD: The study drew data from a study of 262 adults (95.4 % Black/AA) entering residential SUD treatment (NCT#01189552). Assessments were completed at pretreatment and at 3-, 6-, and 12-months posttreatment. Two generalized linear mixed models (GLMM) tested the effects of social support and spiritual well-being, above the effect of 12-step involvement, on substance use frequency and substance use consequences over the course of 12-months posttreatment. RESULTS: Higher spiritual well-being predicted significantly less frequent substance use during recovery (ß = 0.00, p = .03). Greater 12-step involvement predicted significantly fewer substance use consequences during recovery (ß = 0.00, p = .02). In post hoc analyses the effect of spiritual well-being and 12-step involvement dissipated by 3.5- and 6.6-months posttreatment, respectively. The study found no significant effects of social support over time. DISCUSSION: Spiritual well-being and 12-step involvement are associated with lower substance use and substance use consequences, respectively, in the early months of posttreatment recovery among Black/AA adults. These findings contribute to the growing recovery capital literature informing paths to recovery and sources of support outside of 12-step affiliation. However, these effects diminish over time.