Purpose: Wide empirical evidence considers Job Insecurity (JI) as a stressor that leads to poor job-related well-being. With the present study we intend to increase this knowledge by testing how and through what mechanisms JI may give rise to such consequences. In particular, we examined the mediating processes underlying the relationship between JI and Emotional Exhaustion (EE), as an indicator of psychological well-being and core element of burnout. Going beyond previously proposed stress theories, our idea leading to the understanding of these mechanisms concerns theories of social exchange, specifically, Psychological Contract (PC) theory and organizational justice theory. Methodology and Results: A total of 322 blue collar workers in Italy are used to test the hypotheses. The results found support for a model in which the effect of JI on EE was mediated by two variables, i.e. breached PC and perceived distributive injustice (three-path mediational model). Employees who were insecure perceived a breach of their PC, which led to distributive injustice perceptions, which in turn increased EE. Limitations: Cross-sectional data, limit for causal interpretation. Self-report measures, potential source of common method variance. Characteristics of the sample, men and blue-collar workers overrepresented in comparison to the Italian working population. Practical implication: PC breach and distributive injustice may “disturb” the balance between efforts and rewards and consequently may violate the equity principles: thus, organizations need to be careful about what they promise and regarding allocation of outcomes, especially during periods of uncertainty. Originality: The tested model provides a theoretical framework (social exchange theories) that may lead to new insights on the JI-burnout relationship and, in general, on the nature of JI.