This chapter, for consideration at the Research Handbook in Law & Psychology edited by Rebecca Hollander-Blumoff, has three interlinked themes. First, key to legitimation are relational norms that carry identity-related messages about status, equality and respect. Second, relational concerns extend beyond status, value and standing, to include agency, protection and the absence of diminishment and domination (Tyler & Trinkner, 2017; Trinkner et al., 2018; Huq et al., 2017). Third, norm reciprocity operates between police and citizens because legitimacy is a relational, group-based construct. People give up freedoms in exchange for social order, and if the law is enforced and authority is imposed in ways that signal disrespect, arbitrariness and exclusion to those being policed, then they start to question the quid pro quo —they start to query whether power is being exercised not on their behalf, but on them and to them, so they comply and cooperate less readily.