Extending Lloyd, Schmidt, Khondoker, and Tchanturia (2015), this review and meta-analysis evaluated the effectiveness of randomized controlled trials aimed at reducing perfectionism and associated symptoms of depression and anxiety. Of particular interest was the examination of a moderator of delivery method (face-to-face vs. online) in testing the effectiveness of psychological interventions. Also examined is the effect of two structural moderators (control condition type, sample characteristic). A total of 10 studies were identified (65 perfectionism effect sizes, 8 depression effect sizes, and 8 anxiety effect sizes). Psychological interventions were effective in decreasing perfectionism dimensions, depression, and anxiety with medium effect sizes. There were no significant differences in delivery modality, control condition type, and sample characteristic on effect sizes. Findings suggest that psychological interventions are generally effective in reducing perfectionism, although there is no apparent delineation in increasing "adaptive" perfectionism and decreasing "maladaptive" perfectionism. Although comparable benefits were shown in face-to-face and online intervention delivery modes, we suggest prudently incorporating online interventions into clinical practice. (PsycINFO Database Record (c) 2019 APA, all rights reserved).