This chapter explores the role of Hong Kong in cementing, in British eyes, the distinction between extradition and the exercise of extraterritorial jurisdiction. The process of distinguishing these legal mechanisms unfolded through disputes about the Hong Kong government’s treaty right, or lack thereof, to request the surrender of fugitives who had taken refuge in Chinese territory. Taking place during 1843–65, these complex disputes caused British officials to conclude that, unlike other British arrangements with France, the United States, and several other countries, the Sino-British treaty regime for fugitive surrenders was not directly reciprocal. Rather, it gave only China a right of ‘extradition’ and only British Hong Kong a right of ‘exclusive jurisdiction’ over crimes committed within its territory. As such, there was ‘a kind of balanced one-sidedness’ between Britain and China. Retrospectively constructed from evolving ideas of British sovereignty and international reciprocity, this view of the Sino-British treaties influenced British imperial reforms in extradition. It also shaped the legal status of dual British–Chinese subjects in important ways.