The doctrine of sanctification has a troubled history among Pentecostals that stemmed from the debates over perspectives on sanctification that they had inherited from the late nineteenth-century Holiness Movement. The agenda for addressing sanctification is determined by its checkered past. By examining both the history of the doctrine and its locus within the Pentecostal understanding of salvation, this chapter shows that sanctification involves a holistic transformation of the person that enables a deeper participation in the divine nature of holy love. Holiness serves as the crucial connector between initial union in regeneration and final union in glorification. The argument moves from a selective analysis of the history of the doctrine in the Holiness Movement to a focus on the Christological and pneumatological poles of sanctification and concludes by locating its doctrinal impetus within the wider field of Pentecostal soteriology.