Within the scope of the research project „Mental health in the working world - determining the current state of scientific evidence“ by the Federal Institute for Occupational Safety and Health (BAuA), we systematically reviewed studies on fixed-term employment, job insecurity (JI) and its effects on various mental health outcomes. The studies indicate that adverse health consequences of fixed-term employment are moderated by employees’ attitudes as regards the form of employment (e. g. voluntariness) and general life circumstances such as private security needs. Health impact of fixed term employment is furthermore mediated by organizational working conditions – job insecurity in particular. Accordingly, the analysis reveals strong associations between job insecurity and psychological morbidity. The results suggest that an entanglement of fixed-term employment and JI significantly determines the health status of employees. In this paper, we report the outcomes of two scoping reviews, and summarize the findings of the research regarding the associations of fixed-term employment, JI and mental health. Thereby, we discuss the role of job insecurity and further aspects such as stressful working conditions and voluntariness for the health of fixed-term employees.