Quality of goal engagement and alternative goal suppression were investigated in this research. Integrating the dualistic model of passion (Vallerand et al., 2003) with goal-systems theory (Kruglanski et al., 2002), we hypothesized that obsessive passion--associated with recurrent goal-conflicts--would predict greater alternative goal suppression (i.e., goal-shielding) than would harmonious passion--characterized by effective synthesis of the passionate activity with other life domains. Results from 5 laboratory studies supported these hypotheses. In Study 1, participants' dispositional measures of harmonious and obsessive passion were correlated with an implicit measure of goal-shielding. Obsessive (but not harmonious) passion predicted the suppression of alternative goals and the progressive inhibition of unfamiliar goals. In Study 2, we extended these findings by demonstrating the interrelation between quality of goal engagement and goal-commitment such that goal-shielding effects were enhanced, but only for goals in conflict with other life domains (vs. well-integrated goals). In Study 3, the causal influence of passion on goal-shielding was supported via an experimental manipulation of passion. In Study 4, we replicated and extended Studies 1 and 3 by experimentally demonstrating that obsessive (but not harmonious) passion is a mindset conducive to the development of inhibitory links with alternative goals. Study 5 explored the psychological costs associated with repeated unconscious goal suppression by examining its effects on the depletion of self-regulatory resources. Collectively, the present results suggest that the qualitative distinction between obsessive and harmonious passion has implications for the goal-shielding effect and for subsequent self-regulatory behavior.