Scholars and policy makers rely on the theory of procedural justice (PJ) to further the twin goals of improving police-civilian relations and reducing crime. Substantial PJ research demonstrates that civilians evaluate fairness in police-civilian interactions based on voice, neutrality, trust, and respect. Although social identity is an important predictor and outcome of PJ, little research has examined how police officers, who have a unique social identity and sub-culture, evaluate fairness. The current research examined how police officers, as compared to civilians, evaluated fairness through the PJ mechanisms and whether social identity explained differences between the groups. Police officers (
n
= 125), recruited from local law enforcement agencies, and civilians (
n
= 151), recruited from an online participant pool, evaluated a randomly assigned PJ or no-PJ police-civilian interaction. Multiple group analyses and nested model comparisons revealed that the data fit the PJ model best when civilians and police officers were allowed to perceive fairness through different mechanisms. Differences between the samples were explained by self-categorization with the police. The direct effects of respect and gender on fairness, condition on neutrality, condition and voice on respect, and the interaction between condition and self-categorization on voice were responsible for the differences between the samples. Finally, a three-way interaction revealed that civilians who self-categorized less with the police evaluated the PJ condition as providing less voice than more closely identified civilians, who were not different than police. This study replicated and expanded on PJ, policing, and social identity literatures.