Work engagement is a scientifically consolidated variable, due to its fundamental role in business practice. To increase work engagement in companies, it is necessary to know which variables are antecedents and how they relate to each other. These variables include job autonomy, job crafting, and psychological capital. This research evaluates the relationships between job autonomy, job crafting, psychological capital, and work engagement. Specifically, based on the job demands and resources model and the conservation of resources theory, the study examines these relationships in a sample of 483 employees, through a serial mediation model. The results show that job crafting, and psychological capital mediates the relationship between job autonomy and work engagement. These results have practical implications for interventions to promote employee work engagement.