The Church of St. Julian of the Flemings is a Roman Catholic church dedicated to Saint Julian the Hospitaller, located in Rome, Italy. Historically, the church has been the National Church in Rome of the Southern Netherlands and, in 1830, became the national church of the Kingdom of Belgium.

Charitable institutions attached to churches in Rome were founded right through the medieval period and included hospitals, hostels, and others providing assistance to pilgrims to Rome from a certain "nation", which thus became these nations' national churches in Rome. These institutions were generally organized as confraternities and funded through charity and legacies from rich benefactors belonging to that "nation". Often, they were also connected to national scholæ, where the clergymen of that nation were trained. The churches and their riches were a sign of the importance of their nation and of the prelates that supported them. Up to 1870 and Italian unification, these national churches also included churches of the Italian states.