Objectives: to describe scientific evidence on the involvement of companions in patient safety, from their own perspective and health professionals’ perspective in neonatal and pediatric units. Methods: scoping review carried out according to The Joanna Briggs Institute’s recommendations, in eight databases, following the Preferred Reporting Items checklist for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist, between 2011 and 2021. Results: the 13 studies included highlighted the importance of companions’ involvement in patient safety and the prevention of adverse events. However, they pointed out failures in communication and weakness in the training of professionals, which were obstacles to their involvement. The strengthening of health education, multidisciplinary rounds and educational technologies were highlighted as strategies to expand the involvement of companions. Final Considerations: this study directs elements for health professionals and managers to rethink the companions’ role in patient safety and development of collective strategies.