This chapter focuses on migrations from countries with an Orthodox population, their settlement in other parts of the world, and the creation of Orthodox parishes and dioceses in these new areas, with special attention to Western Europe. It deals exclusively with the migration of churches belonging to the Byzantine tradition. The chapter shows that the realities of migration have revealed the challenges facing Orthodox churches resulting from their organisation on national lines. Sometimes, such Orthodox presence has been the result of local initiatives by indigenous groups seeking connections with Orthodox Christianity: in places as varied as Mexico or Uganda, independent local groups have joined the Orthodox Church. In addition, one should not forget ‘spiritual migrants’, those of Western origins who convert to Orthodoxy and contribute to the diversity of Orthodox parishes in the West, but clearly remain a tiny minority of the Orthodox population of European countries.