Minority groups can be highly distrustful of police. This is problematic because it can lead to a reluctance to seek help from police when needed. As a stigmatized minority group, Muslims pose unique challenges for police engagement. This paper explores the importance of both police effectiveness and procedural justice for promoting Muslims’ trust in police. Drawing on survey data collected from 398 Muslims living in Sydney, Australia, this paper tests whether these relationships are person- and context-specific. That is, it examines whether procedural justice or police effectiveness concerns matter most in police- or citizen-initiated contacts with police, and whether individual differences in stigmatization moderate the relationship between procedural justice/police effectiveness on trust. We confirm that Muslims who feel more stigmatized are less likely to trust police, and those who perceive police as more procedurally just and more effective are more likely to trust police. However, results also indicate that the police effectiveness/procedural justice effects are moderated by type of police contact and stigmatization. Procedural justice is more important in police-initiated contacts, while police effectiveness is more important in citizen-initiated contacts. Procedural justice and police effectiveness also more strongly affect trust for those who feel less stigmatized. Together, the results reaffirm the general value of procedural justice and police effectiveness for fostering trust in police but also emphasize that these effects are person- and context-specific.