With the increasing number of women in prison, understanding incarcerated women's psychological health is a timely and necessary line of research to guide policy and practices within prisons. This understanding influences prison design, service coordination, and intervention development. Two main theories commonly shape the examination of women's psychological health during incarceration: deprivation theory and importation theory. Deprivation theory posits that aspects of the prison's environment, such as type of correctional facility, institutional crowding, and type of supervision, influence women's psychological health. In contrast, importation theory focuses on offender-level variables, such as demographics and adversity histories, in connection to incarcerated women's psychological health. This article reviews key research findings from these two theoretical perspectives. An integration of these theories may advance the field of knowledge about women's mental health in prison. Based on both existing research insights and gaps, this article outlines specific implications for theory development and social work research, practice, and policy directions.