This paper considers three possible ways of understanding the claim that the American criminal justice system is racist: individualist, “patterns’-based, and ideology-based theories of institutional racism. It rejects an individualist explanation of institutional racism because such an explanation fails to explain the widespread prevalence of anti-black racism in this system or indeed in the United States. It considers a “patterns” account of institutional racism, where consistent patterns of disparate racial effect mimic the structure of intentional projects of racial subjugation like slavery or Jim Crow. While a “patterns” account helpfully directs attention to the effects of policies and practices that make up an institution, it does not fully explain the deep roots of anti-blackness in the criminal justice system in the United States. The paper concludes by defending an ideology-based theory of institutional racism for understanding the criminal justice system because the stereotype of the black criminal has a mutually reinforcing relationship with the patterns of disparate outcome for black people in the criminal justice system. This relationship creates a looping effect where the stereotype of the black criminal fuels the disproportionate involvement of black people in the criminal justice system, and the disproportionate representation of black people with felony records, in prisons, brutalized in police encounters, and so on reinforces the idea that black people are especially prone to criminality. Ideological approaches to racism that integrate attention to the patterns of disparate effect best explain what it means to say that the criminal justice system is racist.