Purpose - The numbers of health care transparency initiatives are increasing. Despite the growing availability of quality data, there seems to be a shortage of evidence about the effects and effectiveness of such initiatives. The aim of this systematic review is to document the effects of transparency, defined as the public release of quality performance data, on hospital care outcomes.Design/methodology/approach - Through a review of the literature, we chose 46 keywords to use in our searches and focused on empirical studies published in English between 2010 and 2015. The use of combinations of these keywords in searches of four databases (PubMed, Scopus, Web of Science, and the Cochrane Library) generated 13,849 publications. The removal of duplicates and exclusion of studies that were not empirical or not relevant to transparency and quality resulted in 39 studies to be reviewed.Findings - Our review of the literature confirmed the growth of health care transparency efforts, led by the United States, and found mixed results regarding the effects of transparency on hospital care outcomes. For example, mortality, the most frequently researched performance measure (n = 15), exhibited this mixed pattern by having studies showing a reduction (n = 4), increase (n = 1), mixed findings (n = 4), and no significant relationship (n = 6) as a result ofpublic release. We also found a limited number of articles related to unintended consequences of public reporting. When compared with earlier systematic reviews, there seems to be a trend in the reduction of unintended consequences. Therefore, we recommend exploration of this potential trend in future studies empirically.Practical Implications - The research findings summarized in this systematic review can be used to understand the results of existing transparency efforts and to develop future transparency initiatives that may better enhance hospital quality performance.Originality/value - This is the latest and most comprehensive systematic review summarizing the effects of transparency of quality metrics on hospital care outcomes.