In the paper the author analyzed the citizenship norms in the Croatian-Slavonian area in the Kingdom of Serbs, Croats and Slovenes in the period from the formation of the state in 1918 to the first Citizenship Law of the Kingdom of Serbs, Croats and Slovenes, which entered into force on 1 November 1928. Based on practical examples the author analyzed the relevance of various groups of norms in citizenship cases. In doing so, the author analyzed the concept of Croatian-Slavonian citizenship law in the new state, further application of abolished norms in administrative practice and application of Serbian citizenship law and other norms in the Croatian-Slavonian area. Based on the analyzed sources the author pointed out the competition of various norms and concluded that the normative complexity significantly complicated the process of standardization of citizenship law in the Croatian-Slavonian area. In addition, the author argues for a reformulation of the current understanding of the citizenship setting, which presupposes initial validity of citizenship norms enacted before 1 December of 1918 and their gradual change with new citizenship norms enacted over the following ten years. Instead, the author argues that this was only dominant practice, which was in a number of cases faced with other normativities that represented competitive solutions.