Considering the mixed results of the relationship between job insecurity and job performance, this study investigated the interaction effect of job insecurity and job embeddedness on job performance and examined the mediating role of affective commitment from the perspectives of conservation of resources theory and social exchange theory. A survey of 725 contract employees from two Chinese private manufacturing companies revealed that when employees had high levels of job embeddedness, job insecurity was significantly and positively related to job performance. In contrast, job insecurity was significantly and negatively related to job performance when there were low levels of job embeddedness. Furthermore, the results indicated that affective commitment mediated the interaction effect. The above conclusions not only illustrate the important role of job embeddedness in the relationship between job insecurity and job performance but also provide beneficial ideas and information to organisations and employees for managing job insecurity.