Purpose This systematic review sought to summarize published professionalism curricula in postgraduate medical education (PGME) and identify best practices for teaching professionalism. Method Three databases (MEDLINE, Embase, ERIC) were searched for articles published from 1980 through September 7, 2017. English-language articles were included if they (1) described an educational intervention addressing professionalism, (2) included postgraduate medical trainees, and (3) evaluated professionalism outcomes. Results Of 3,383 articles identified, 50 were included in the review. The majority evaluated pre- and posttests for a single group (24, 48%). Three (6%) were randomized controlled trials. The most common teaching modality was small-group discussions (28, 56%); other methods included didactics, reflection, and simulations. Half (25, 50%) used multiple modalities. The professionalism topics most commonly addressed were professional values/behavior (42, 84%) and physician well-being (23, 46%). Most studies measured self-reported outcomes (attitude and behavior change) (27, 54%). Eight (16%) evaluated observed behavior and 3 (6%) evaluated patient outcomes. Of 35 studies that evaluated statistical significance, 20 (57%) reported statistically significant positive effects. Interventions targeting improvements in knowledge were most often effective (8/12, 67%). Curriculum duration was not associated with effectiveness. The 45 quantitative studies were of moderate quality (Medical Education Research Study Quality Instrument mean score = 10.3). Conclusions Many published curricula addressing professionalism in PGME are effective. Significant heterogeneity in curricular design and outcomes assessed made it difficult to synthesize results to identify best practices. Future work should build upon these curricula to improve the quality and validity of professionalism teaching tools.