Many software developing companies use Quality Gates to mitigate quality problems and to steer projects in time. The necessary structures, activities, methods, roles and documents can be encapsulated in a Quality Gate reference process, which then can be tailored to fulfill the needs of different projects. Each company has to implement a Quality Gate reference process individually because quality and business goals differ. In order to improve the quality of a Quality Gate reference process a company has to assess the quality of the implemented Quality Gate reference process. This paper presents a concept allowing the conduction of such an assessment by assessing the concepts of a Quality Gate reference process separately. The concepts (which have to be assessed) were identified by an empirical study involving several companies and by analyzing current literature. The assessment concept was validated by assessing the quality of different Quality Gate reference processes from literature.