The migration period was a period in European history marked by large-scale migrations that saw the fall of the Western Roman Empire and subsequent settlement of its former territories by various tribes. The term refers to the important role played by the migration, invasion and settlement of various tribes, notably the Franks, Goths, Alemanni, Alans, Huns, the early Slavs, Pannonian Avars, Magyars, and Bulgars within or into the former Western Empire and Eastern Europe. The period is traditionally taken to have begun in CE 375 (possibly as early as 300) and ended in 568. Various factors contributed to this phenomenon of migration and invasion, and their role and significance are still widely discussed.

Historians differ as to the dates for the beginning and ending of the Migration Period. The beginning of the period is widely regarded as the invasion of Europe by the Huns from Asia in about 375 and the ending with the conquest of Italy by the Lombards in 568, but a more loosely set period is from as early as 300 to as late as 800. For example, in the 4th century a very large group of Goths was settled as foederati within the Roman Balkans, and the Franks were settled south of the Rhine in Roman Gaul. Another pivotal moment in the Migration Period was the Crossing of the Rhine in December of 406 by a large group of tribes including Vandals, Alans and Suebi who settled permanently within the crumbling Western Roman Empire.