•Interprofessional simulation-based learning (ISBL) can strongly affect student self-efficacy contribution.•Students’ experiences with how ISBL contributes to self-efficacy is described.•In ISBL, all of Bandura's sources for the development of self-efficacy can be identified.•To positively affect students’ self-efficacy, ISBL needs to be well-designed/prepared. Self-efficacy is an essential concept regarding academic performance and persistence in higher education. Research indicates that interprofessional simulation-based learning influences participants’ self-efficacy and points to a need for more research on self-efficacy and its development. This study describes perioperative nursing students’ experiences with how interprofessional simulation-based learning contributes to self-efficacy in communication, interdisciplinary collaboration, and prioritising tasks in acute situations. Six qualitative focus group interviews were conducted with thirty-four perioperative nursing students from four universities and university colleges in Norway. Qualitative directed content analysis was applied in accordance with Bandura's social cognitive theory which specifies four sources influencing self-efficacy. Results showed that well-designed/prepared interprofessional simulation-based learning can develop self-efficacy concerning communication, interdisciplinary collaboration, and prioritising tasks in acute situations.