Purpose: Employee engagement (EE), supervisor support (SS) and interprofessional collaboration (IPC) are important contributors to patient safety climate (PSC). The purpose of this paper is to propose and empirically test a model that suggests the presence of a three-way interaction effect between EE, IPC and SS in creating a stronger PSC. Design/methodology/approach: Using validated tools to measure EE, SS, IPC and PSC data were collected from a questionnaire of 250 clinical and support staff in an Australian health service. Using a statistical package (SPSS) an exploratory factor analysis was conducted. Bivariate correlations between the derived variables were calculated and a hierarchical ordinary least squares analysis was used to examine the interaction between the variables. Findings: This research finds that PSC emerges from synergies between EE, IPC and SS. Modelling demonstrates that the effect of IPC with PSC is the strongest when staff are highly engaged. While the authors expected SS to be an important predictor of PSC; EE has a stronger relationship to PSC. Practical implications: These findings have important implications for the development of patient safety programmes that focus on developing excellent supervisors and enabling IPC. Originality/value: The authors provide quantitative evidence relating to three of the often mentioned constructs in the typology of patient safety and how they work together to improve PSC. The authors believe this to be the first empirically based study that confirms the importance of IPC as a lead marker for improved patient safety.