Police legitimacy: a measurement model. The purpose of this paper is to develop a measurement model of the sentiments of police legitimacy among São Paulo citizens. National survey-based research on public attitudes towards the legal authorities commonly adopts an operationalist approach, ignoring the gap between concepts and survey questions. We contribute substantively to this research field by developing a measurement model of police legitimacy, which is conceptually defined as a normatively grounded duty to obey the police and a moral alignment with the police. Using data from a representative survey of eight regions of the city of São Paulo in 2017, we performed a second-order confirmatory factor analysis. Subsequentely, we estimated a structural equation model centered on the legitimacy construct so as to validate the measure. Policy implications of both the concept and the measurement of police legitimacy are discussed. doi.org/10.1590/3410007/2019. Replication materials here.