There is a gap between the demand and supply of efficiency analyses within primary care (PC), despite the threatening financial sustainability of health care systems. This paper provides a systematic literature review on PC efficiency analysis using Data Envelopment Analysis (DEA). We reviewed 39 DEA applications in PC, to understand how methodological frameworks impact results and influence the information provided to decision makers. Studies were combined using qualitative narrative synthesis. This paper reports data for each efficiency analysis on the: 1) evaluation context; 2) model specifications; 3) application of methods to test the robustness of findings; 4) presentation of results. Even though a consistent number of analyses aim to support policymakers and practice managers in improving the efficiency of their PC organizations, the results indicate that DEA--at least when applied to PC--is a methodology still in progress; it needs to be further advanced to meet the complexity that characterizes the production of PC outcomes. Future studies are needed to fill some gaps in this particular domain of research, such as on the standardization of methodologies and the improvement of outcome research in PC. Most importantly, further studies should include extensive uncertainty analyses and be based on good evidence-based rationales. We suggest a number of considerations to academics and researchers to foster the utility of efficiency measurement for the decision making purposes in PC.