The present study used a latent growth curve modeling approach to (1) examine the effectiveness of a brief self-compassion intervention on reducing impostor phenomenon and its related psychological distress and (2) explore who would benefit most from this intervention. A total of 227 college students at a large Midwest university were randomly assigned to participate in either a four-week brief self-compassion intervention group or a non-intervention control group. The results of the effectiveness of the intervention suggested the brief self-compassion intervention had significant treatment effects for three outcomes (i.e., impostor phenomenon, maladaptive perfectionism, and psychological well-being), but not for the other two outcomes (i.e., depression and anxiety) at the posttest and 1-week follow-up assessments. Two psychological constructs were tested to investigate if they would moderate the effects of the brief self-compassion intervention on impostor phenomenon and its related psychological distress over time. The first moderator was fear of self-compassion. For impostor phenomenon, fear of self-compassion failed to be a significant moderator of the treatment effects over time. For the three negative psychological outcomes (i.e., maladaptive perfectionism, depression, and anxiety), fear of self-compassion was a significant moderator of the intervention effects of the brief self-compassion intervention. Simple effect analyses indicated that participants with higher levels of fear of self-compassion reported a significant decrease in maladaptive perfectionism, depression, and anxiety across the three time points, whereas those with lower levels of fear of self-compassion did not experience significant change over time across these three outcomes. For psychological well-being, the results from the simple effect analyses showed participants with higher levels of fear of self-compassion reported a significant increase in psychological well-being whereas those with lower levels of fear of self-compassion did not report a significant increase in psychological well-being. Thus, the brief self-compassion intervention was more beneficial for participants with greater fear of self-compassion. The second moderator was core self-evaluation. For impostor phenomenon, core self-evaluation failed to significantly moderate the intervention effects over time. For the three negative psychological outcomes (i.e., maladaptive perfectionism, depression, and anxiety), core self-evaluation was a significant moderator of the treatment effects of the brief self-compassion intervention. Simple effect analyses suggested that participants with lower core self-evaluation reported a significant decrease in the three psychological outcomes whereas those with high core self-evaluation did not experience significant change over time across the three outcomes. For psychological well-being, participants with lower levels of core self-evaluation reported a significant increase in psychological well-being whereas those with higher levels of core self-evaluation did not experience a significant change in psychological well-being. Thus, the brief self-compassion intervention was more beneficial for participants with lower core self-evaluation. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]