Foreign judges play an important role in the constitutional or apex courts of a range of countries. Comparative constitutional scholars, however, have to date paid limited attention to this phenomenon of “internationalized“ or “hybrid“ constitutional courts. This article thus addresses this gap in comparative constitutional scholarship by providing a general framework for understanding the potential advantages and disadvantages to hybrid models of constitutional justice. It suggests that the attractiveness of hybrid constitutional models will generally depend on the answer to five key questions – i.e. whyforeign judges are appointed to a court and the degree of local democratic support for their appointment, who the foreign judges are, by what means are they appointed and paid and how their terms in office are structured, how foreign judges approach their adjudicatory role, and when they exercise their role.