Background. Missed nursing care, which has been explored in various acute care settings, results in adverse patient outcomes and job dissatisfaction in nurses. However, little is known about missed care in the operating room. Objective. This study tested a hypothesised model to identify relationships between nurses’ age, years of experience in the operating room, job satisfaction, and intention to leave which have direct and indirect effects on the frequency of missed care. The frequency of missed care was hypothesised to be mediated by nurses reported perioperative competence and the reasons for missed care. Design. A cross-sectional design using an online survey of Australian perioperative nurses was undertaken in 2022. Methods. All Australian College of Perioperative Nurses members were invited to participate. Missed nursing care was measured using the MISSCARE Survey-OR. Age, years of experience, and intention to leave were single-item measures. Satisfaction was a three-item scale. Competence was measured by the 18-item Perceived Perioperative Competence Scale-Short Form. Structural equation modelling was used to test our hypothesised model. Results. Of the 5,500 nurses invited, 853 (15.5%) responded, but only 602 (10.9%) participant responses were usable for inclusion in the model. The model demonstrates that participants’ age directly predicted the frequency of missed care, nurse role satisfaction, perceived perioperative competence, and reasons for missed care. The reasons for missed care and perceived perioperative competence were mediators that were negatively associated with the frequency of missed care. Conclusions. While the final model explained 22.6% of the frequency of missed care, other variables not identified in this study may influence this outcome.