Previous research has shown that job insecurity is linked to a range of performance outcomes, but the number of studies exploring this relationship is still limited and the results are somewhat mixed. The first aim of this study was to meta-analytically investigate how job insecurity is related to task performance, contextual performance, counterproductive work behavior, creativity, and safety compliance. The second aim was to test two method-related factors (cross-sectional vs. longitudinal associations and self- vs. supervisor-ratings of performance) and two macro-level indicators of social protection (social welfare regime and union density) as moderators of these associations. The results show that job insecurity was generally associated with impaired employee performance. These findings were generally similar both cross-sectionally and longitudinally and irrespective of rater. Overall, the associations between job insecurity and negative performance outcomes were weaker in welfare regimes characterized by strong social protection, whereas the results concerning union density produced mixed results. A majority of the findings confirmed the negative associations between job insecurity and types of employee performance, but future research is needed to elaborate on the effects of temporal aspects, differences between ratings sources, and further indicators of social protection in different cultural settings in the context of job insecurity.