PurposeThis article explores the roles and the expertise of Hong Kong in the internationalization of public administration education.Design/methodology/approachThe methodology is based on the data of 5 internationalization initiatives of one Hong Kong university with its internationalization partners in Macau, Korea, Australia, Russia and Finland. The data obtained lasted for a period of 18 months, from September 2019 to March 2021.FindingsThe finding of this study revealed that (1) there are 5 “pubtropolis roles” (roles of a public administration metropolis) of Hong Kong in the internationalization of public administration education in China, Asia, Asia-Pacific, Belt-and-Road and Europe. The findings also revealed that (2) Hong Kong served as a pubtropolis with its “5C” expertise in curriculum innovation, customized training, competence framework, competence assessment and comparative policy.Research limitations/implicationsAs the methodology of this article is based on the data of 5 internationalization initiatives of one Hong Kong university by one academia only, further studies can be conducted at department, faculty or university level for multiple academia.Practical implicationsThere are two practical implications: (1) The more the roles of a city, the broader the view in its internationalization of public administration initiatives; (2) Hong Kong could further tap on its expertise in “5C” in public administration: curriculum innovation, customized training, competence framework, competence assessment and comparative policy to exert its “geo-management” power.Social implicationsThis article argues that public services can be improved by the setting up of “Sabbatical Leave Scheme for Internationalization of Public Administration” by respective governments to sustain the impacts observed.Originality/valueIt is from the author's original work.