In recent years, organizational needs and interested parties’ demands have increased the necessity to utilize multiple management system standards. Especially since more and more organizations must comply to more than one management system at a time. To utilize multiple management systems standards within one integrated overall management system of an organization, requirements of the relevant standards need to be linked and consolidated. As every organization manages its activities, resources and objectives through a set of interrelated processes this will lead to a generic process reference model for management systems. A generic – management system model – using a process approach is not present and needs to be developed. This article aims to fill this research gap by proposing such a generic process reference model across multiple management systems. The model was developed by using a multi-model harmonization method with process reference models for information privacy, information security and the ISO handbook on the integrated use of management systems (IUMSS).