Mass incarceration is the jailing and imprisonment of a disproportionately large population in the United States, compared to international practices and historical precedents, especially affecting minority and impoverished communities. Drawing on ethnographic fieldwork with individuals, congregations, and organizations involved in prison ministry, activism, and education, this project will explore the theological and moral commitments that draw Christians into practices related to criminal justice systems and how Christians have embodied and reimagined these commitments as they have engaged in prison ministry, activism, and education. The sites for the study include Healing Communities, a non-profit organization based in Philadelphia that works with congregations to provide services to people in prison, people re-entering their communities, and their families; the program at Lee Arrendale State Prison for a Certificate in Theological Studies (CTS), which is operated by the Atlanta Theological Association to provide a year-long course of theological studies to women in prison; and Black Lives Matter, an activist network including many Christians who oppose mass incarceration. The study will situate this fieldwork within social movement theory and examine the theological, political, social, and cultural motivations of people involved in efforts to mitigate mass incarceration.