This contribution maps recent global trends regarding the grounds for acquisition of citizenship by descent and by birth on a particular territory. Questions of nationality law have traditionally been part of the State’s reserved domain. However, it will be seen that some of the trends regarding citizenship acquisition by ius sanguinis and ius soli can be attributed to the inroads made by international law into the rule that each State has absolute autonomy in deciding who its citizens are. Others are the result of the still considerable leeway available to States in nationality matters. Against the backdrop of the current international standards and drawing on data collected by the GLOBALCIT Observatory for 174 countries on five continents, the article analyses national practices in respect of the acquisition by ius sanguinis and ius soli, remedial ius soli for otherwise stateless children, and the nationality effects of the recognition of paternity.