This study hypothesizes the gradual emergence of a defence and security constitution within the broader constitutional and state-building processes of the Hungarian part of the Austro-Hungarian Empire. While the 1867 Compromise established a dualist constitutional framework for political governance, it also triggered a parallel institutional and legal evolution in the field of state defence and security. The evolution of this defence and security constitution and the modernization of Hungary’s defence system - beyond their historical significance - might offer a valuable framework for addressing today’s security challenges. The research draws on primary sources, including legal texts and historical documents, as well as secondary literature and employs a historical-legal approach, analyzing the development of Hungary’s defence institutions and their constitutional framework.