This study examined the effects of bystander or victim intoxication during a crime on juror perceptions and decision-making. Mock jurors (N = 261) read testimony from a bystander or victim to an assault, who mentioned that they had consumed alcohol, cannabis, amphetamines, or no substances prior to the crime. Participants delivered a verdict, rated the defendant’s guilt, and rated the bystander/victim on their honesty, credibility, and cognitive competence. Witness intoxication and witness role did not influence defendant guilt. However, participants judged any witness intoxicated by amphetamines as less credible and cognitively competent than a sober witness. Furthermore, victims were judged to have lower credibility, cognitive competence, and honesty than bystanders. These findings suggest that jurors’ decision-making about defendant guilt might not be influenced by witness intoxication or witness type. A witness’ testimony, however, might be evaluated as less credible when delivered by a victim or an amphetamine-intoxicated witness.