Black Americans experience more frequent guilty verdicts and harsher sentences in the criminal justice system. However, recent laboratory work often finds either trivial differences or a pro-Black bias where people provide more lenient verdicts for Black versus White defendants. Across five studies, we find a consistent pro-Black bias even after reducing social desirability concerns. Instead, the pro-Black bias results from a negative relationship between perceived anti-Black criminal justice bias and the Black suspect’s verdict. The current work shows the pro-Black bias as a consequence of the newly salient perception of racial bias in the criminal justice system. Consequently, as people’s perceptions of racial disparities in the criminal justice system increase, this in-lab effect may manifest in real-world criminal justice outcomes.