Objective: Although research on the personal and psychosocial predictors of doping has been extensive, the factors related to the socio-cognitive self-regulatory mechanisms of doping remain unexplored. The aim of this study was to test an integrated multi-theory model examining the role of self-determined motivation in sport in the self-regulatory mechanisms of doping intentions in elite athletes. Methods: A cross-sectional survey was employed. Two hundred and sixty-four elite athletes completed a survey that included measures of self-determination (autonomous vs. controlled), affective self-regulatory efficacy, resistive self-regulatory efficacy, moral disengagement, and doping intentions. Results: Structural equation modeling showed that the model predicted 47.3% of the variance in doping intentions and indicated that both autonomous and controlled motivations were indirectly associated with doping intentions through the mediating role of affective self-regulatory efficacy, resistive self-regulatory efficacy, and moral disengagement. Conclusion: Self-determination theory provides insight into how motivation in sport influences athletes' doping intentions through its impact on socio-cognitive self-regulatory mechanisms.