BACKGROUND: To investigate whether usage of treatment-acquired regulatory skills is associated with prevention of depressive relapse/recurrence. METHOD: Remitted depressed outpatients entered a 24-month clinical follow up after either 8 weekly group sessions of cognitive therapy (CT; N = 84) or mindfulness-based cognitive therapy (MBCT; N = 82). The primary outcome was symptom return meeting the criteria for major depression on Module A of the SCID. RESULTS: Factor analysis identified three latent factors (53% of the variance): decentering (DC), distress tolerance (DT), and residual symptoms (RS), which were equivalent across CT and MBCT. Latent change score modeling of factor slopes over the follow up revealed positive slopes for DC (β = .177), and for DT (β = .259), but not for RS (β = -.017), indicating posttreatment growth in DC and DT, but no change in RS. Cox regression indicated that DC slope was a significant predictor of relapse/recurrence prophylaxis, Hazard Ratio (HR) = .232 90% Confidence Interval (CI) [.067, .806], controlling for past depressive episodes, treatment group, and medication. The practice of therapy-acquired regulatory skills had no direct effect on relapse/recurrence (β = .028) but predicted relapse/recurrence through an indirect path (β = -.125), such that greater practice of regulatory skills following treatment promoted increases in DC (β = .462), which, in turn, predicted a reduced risk of relapse/recurrence over 24 months (β = -.270). CONCLUSIONS: Preventing major depressive disorder relapse/recurrence may depend upon developing DC in addition to managing residual symptoms. Following the acquisition of therapy skills during maintenance psychotherapies, DC is strengthened by continued skill utilization beyond treatment termination. (PsycINFO Database Record (c) 2019 APA, all rights reserved).