Although previous empirical research has provided insight into the link between perceived job insecurity and mental health, many questions remained unanswered. These include to what extent job insecurity has a mental health effect when controlling for (unobserved) individual characteristics, and to what extent there is effect heterogeneity. This dissertation therefore focuses on the mental health effect of job insecurity controlling for individual characteristics as well as the moderating effect of various demographic, sociological, and psychological variables. More specifically, it examined, next to a main effect, the role of gender, age, family situation, education, income, type of employment contract, religiousness, personality, and self-efficacy. By using a fixed effects estimator to control for time-invariant unobserved characteristics and data from the Netherlands for 2008-2018 chapter 2 indicates a rather small mean effect of perceived job insecurity on mental health. Some groups, however, have more trouble than others in dealing with perceived job insecurity: men, esp. with intermediate and higher levels of education, and with permanent contracts. Furthermore, negative effects of job insecurity increase with income. The moderating role of religiousness in the mental health effect of job insecurity could go either way: buffer or burden. Chapter 3 finds that religious employees in general, and Protestants among them in particular, despite being at risk due to a higher work ethic, are shielded from the adverse mental health effects of job insecurity. Instrumental are belief beyond doubt in God's existence as well as belief in life after death. The beliefs in God and in afterlife only appear to insulate workers who frequently attend religious gatherings. It is unclear how well people with different personality traits deal with a real-life stressor such as job insecurity. Chapter 4 investigates the interaction between the Big5 traits and job insecurity on mental health in three large, representative household ...