This chapter discusses several of the key attributes of the rule of law and explores their relevance for Canadian administrative law: the rule of law as an unwritten constitutional principle; the rule of law as a political ideal which structures institutional relations and competencies; and, the rule of law as a distinctive political morality which, in Canada, is understood as a dialogue among the three branches of government. The chapter assesses the Canadian articulation of the rule of law in the jurisprudence of the Supreme Court of Canada, then turns to the contemporary judicial review of administrative action. Recent case law illustrates how the rule of law informs how judges engage with statutes through the modern approach to interpretation, motivates deference to other branches of government, and facilitates the creation of common law constraints on the exercise of discretion. This substantially revised chapter takes into account several important jurisprudential developments that have occurred since the first edition: recent pronouncements on the concepts of fairness and arbitrariness in administrative law; the new focus on the adequacy of reasons within the reasonableness standard of review; the marginalization of the correctness standard in favour of the reasonableness standard; and, the new approach to the judicial review of discretionary decisions implicating Charter values announced in Doré v Barreau du Québec, 2012 SCC 12.