Engagement is foundational for parents involved in the child welfare system. In this motivation theoretical analysis, we use self-determination theory (SDT) as a framework to organize the extant literature and explain why key casework practices promote parent engagement; offer guidance for caseworkers to recognize indicators of disaffection in their interactions with parents; and illustrate ways to adjust casework practice to better support parent engagement. The analysis points to the importance of caseworker skills in promoting parent engagement, the reciprocal nature of engagement work, and the need for child welfare agencies to similarly provide motivational supports for caseworkers. Promoting parent engagement, and supporting caseworkers in doing this challenging work, is an important pathway toward improving outcomes for parents, children, and families.