Equine-facilitated prison programs have become more prevalent and operate in correctional facilities in 13 states throughout the United States. However, there is a deficit of empirical knowledge to guide them. This article reviews 19 studies of prison-based animal programs and centers on patterns in the literature. It reveals how previous studies are relevant and how they can be applied to the examination of equine-facilitated prison-based interventions. Research of this field is warranted in order to study issues, such as the effectiveness of these programs, suitable participants for such programs and contraindications, and the impact of these programs on variables such as recidivism and disciplinary misconduct.