Background E-professionalism is a term used to describe the behaviours of healthcare professionals, including nurses, in the online environment. While a range of professional guidance on the use of online social media platforms is available, there has been little research into the perspectives of patients and the public more generally on nurses’ e-professionalism.

Aim To explain what, how and why the public make decisions about the acceptability of nurses’ online behaviours and e-professionalism, and to make recommendations for nurses on managing the information they share online.

Method This was a mixed-method critical realist study. Participants in a survey (n=53) and two focus groups (n=8) discussed and rated the acceptability of five vignettes related to nurses’ online behaviours based on real-life examples.

Findings The participants generally thought that nurses are entitled to have a personal life and freedom of speech and to promote causes they believe to be important, even if these were not aligned with their own beliefs. Participants unanimously considered the use of profane language against any individuals or groups to be unacceptable.

Conclusion The public make decisions on the acceptability of nurses’ online behaviours based on a range of complex factors, including social and individual values, attitudes and beliefs, as well as their intent and consequences. Recommendations for nurses on how to manage the information they share online include: using separate platforms for personal, educational and professional purposes; using functions that control who can ‘tag’ and share their posts; and ensuring any information they share that relates to healthcare or nursing practice is up to date and evidence based.