The private security industry has expanded rapidly in recent decades. Yet the sector has been plagued by suggestions that its personnel lack the professionalism, skills, effectiveness and legitimacy to perform many of the tasks they are employed to do. This raises questions of how the sector has or should attempt to enhance their perceived legitimacy. The current study tests whether citizens’ perceptions about procedural justice might be associated with legitimacy judgements in the private security sector. Specifically, it explores whether citizens focus more on procedural justice concerns or effectiveness concerns when forming judgements about the legitimacy of frontline private security practitioners. Using survey data from 347 Australian citizens, the findings show that procedural justice concerns are most strongly associated with citizens’ legitimacy evaluations; concerns about effectiveness seem to be less important. Further inspection of the data reveals that the ‘neutrality’ and ‘trustworthiness’ sub-components of procedural justice are what matters to Australian citizens. The implications of these findings for scholarship and practice in the private security sector are discussed.