AimTo investigate predictors of nurses' reporting behaviours and their reasons for not formally reporting.BackgroundUnderreporting of workplace violence (WPV) among nurses contributes to gaps in WPV prevention measures, as it cannot be fully understood. WPV is classified according to its source (Type II: patients and visitors, Type III: coworkers) and forms (physical assault, threat of assault, emotional abuse, verbal sexual harassment and sexual assault).DesignThis is a secondary analysis of cross-sectional survey data collected in 2019 from British Columbia (BC), Canada.MethodsThis study had a sample of 4109 BC nurses. Multinomial logistic regression was used to analyse predictors of reporting behaviours. Reasons for not reporting were analysed descriptively.ResultsInformal reporting to management or through a patient safety incident report was less likely when nurses experienced threat of assault, emotional abuse and verbal sexual harassment from both Type II and III sources and physical assault from Type III sources. Higher perceptions of WPV prevention efforts increased odds of informal and formal reporting through employee incident procedures. Believing that nothing would change after reporting remained among the top three reasons for not formally reporting across all WPV sources and forms. Nurses also commonly selected not knowing the formal process, lack of leadership support and other reasons stated in an open-text response.ConclusionFindings indicate that nurses in BC, Canada, perceive many barriers to formal WPV reporting. Formal reporting systems should address these barriers so that healthcare organisations can effectively track WPV and have data to inform WPV prevention measures.ImplicationsTo promote WPV reporting, healthcare organisations need multifaceted interventions including confidential and simplified reporting systems, leadership support to follow-up with nurses and education and training on reporting systems.Reporting MethodThe authors of this manuscript have adhered to the relevant EQUATOR guidelines based on the STROBE cross-sectional reporting method.Patient or Public ContributionNo patient or public contribution.