This article is an attempt to present Thomas Aquinas’s theory of work and to complement it with his reflections on Christ’s work, by gathering together various elements of such a theory, both philosophical and theological, that are found dispersed throughout his writings. It begins by elaborating Aquinas’s definition of work, before considering various aspects of the concept, including its finality and place within the hierarchy of human activities, and its role as a cooperation with the creator. The penal aspects of work are also investigated. The paper concludes with a discussion of Thomas’s Christological principles and of Christ’s work and its implications for a theology of work.