This chapter lays out the legal framework that enabled Hong Kong’s multiracial residents to engage with Britishness. It explains how the British nationality law enabled multiracial inhabitants in pre-war Hong Kong to make claims to Britishness. Using immigration cases, guidebooks, and census reports, this chapter shows when, by whom, and to what extent this inclusive legal status was recognized. Racial presumptions often prompted officials to deny people of colour access to their legal entitlements as British subjects. Nevertheless, colonial subjects in Hong Kong became increasingly aware of their British status, with some making active claims to their rights. In exploring the understanding and usage of British nationality law in 1910–45 Hong Kong, this chapter illuminates how nationality and citizenship were understood in an era when such concepts remained relatively new.