Background: Despite the proven effectiveness of rapid initiation of cardiopulmonary resuscitation (CPR) for patients with out-of-hospital cardiac arrest (OHCA) by bystanders, fewer than half of the victims actually receive bystander CPR. We aimed to review the evidence of the barriers and facilitators for bystanders to perform CPR. Methods: This scoping review was conducted as part of the continuous evidence evaluation process of the International Liaison Committee on Resuscitation (ILCOR), and followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. This review included studies assessing barriers or facilitators for the lay rescuers to perform CPR in actual emergency settings and excluded studies that overlapped with other ILCOR systematic reviews/scoping reviews (e.g. dispatcher instructed CPR etc). The key findings were classified into three kinds of factors: personal factors; CPR knowledge; and procedural issues. Results: We identified 18 eligible studies. Of these studies addressing the reduced willingness to respond to cardiac arrest, 14 related to "personal factors", 3 to "CPR knowledge", and 2 to "procedural issues". On the other hand, we identified 5 articles assessing factors increasing bystanders' willingness to perform CPR. However, we observed significant heterogeneity among study populations, methodologies, factors definitions, outcome measures utilized and outcomes reported. Conclusions: We found that a number of factors were present in actual settings which either inhibit or facilitate lay rescuers' performance of CPR. Interventional strategies to improve CPR performance of lay rescuers in the actual settings should be established, taking these factors into consideration.