Prosecutors exercise substantial discretion within the criminal justice process, potentially allowing for discrepant treatment of criminal cases. The purpose of this research was to examine the association between prosecutorial implicit biases and victim gender and sexual orientation in an intimate partner violence (IPV) case. Participants, 201 prosecutors from across the United States, completed two Implicit Association Tests to measure implicit gender attitudes and implicit attitudes regarding lesbian, gay, bisexual, and queer individuals. Participants were randomly assigned to one of four conditions (opposite-sex couple/female victim, opposite-sex couple/male victim, same-sex couple/female victim, same-sex couple/male victim) and read a case file of an alleged IPV arrest. Consistent with our hypotheses, prosecutors were 65% more likely to prosecute under the severest criminal penalty when the victim was female or included an opposite-sex couple. However, we found no evidence that implicit biases related to prosecutorial decisions.