This article analyses the principle of proportionality as a foundational doctrine of administrative law and administrative procedure in the Republic of Kazakhstan. It examines the principle’s philosophical underpinnings and legal foundations, its codification in the Administrative Procedure and Process Code, and its interpretation in the jurisprudence of the Constitutional Court and the Supreme Court. The study further incorporates a comparative perspective, drawing on selected foreign legislative frameworks and judicial practices. Particular attention is devoted to case law illustrating both effective and problematic applications of the proportionality principle. The article argues for the development of clear methodological criteria to assess the suitability, necessity, and proportionality of administrative measures. It also underscores the importance of professional training for public officials and judges, the strengthening of judicial review mechanisms, and the careful adaptation of best international practices.