This article seeks to constructively retrieve Anselm’s theology of the Holy Spirit by responding to a recent criticism of his doctrine of atonement. This criticism is called the question of efficacy and focuses particularly on how Anselm holds humanity to participate in and receive the divine gift of atonement. In short, this paper argues that the Spirit’s prevenient and subsequent grace allow for an individual to respond freely and in faith to Christ’s work, resulting in three individually necessary and jointly (...) sufficient conditions for union to be restored with God and human flourishing to obtain in Anselm’s thinking. In order to argue this, the paper proceeds in four sections. First, it discusses the question of efficacy. Second, it discusses the Spirit’s work in relation to an individual initially accepting Christ’s Gift. The paper then proceeds by discussing the subsequent work of the Spirit and redemptive role of faith that are inherently tied to the initial work. The paper then concludes by analyzing alternative approaches to this question of efficacy. (shrink)