Ethnology (from the Greek ἔθνος, ethnos meaning "people, nation, race") is the branch of anthropology that compares and analyzes the origins, distribution, technology, religion, language, and social structure of the ethnic, racial, and/or national divisions of humanity.

Compared to ethnography, the study of single groups through direct contact with the culture, ethnology takes the research that ethnographers have compiled and then compares and contrasts different cultures. The term ethnology is credited to Adam Franz Kollár who used and defined it in his Historiae ivrisqve pvblici Regni Vngariae amoenitates published in Vienna in 1783. Kollár's interest in linguistic and cultural diversity was aroused by the situation in his native multi-lingual Kingdom of Hungary and his roots among its Slovaks, and by the shifts that began to emerge after the gradual retreat of the Ottoman Empire in the more distant Balkans.

Among the goals of ethnology have been the reconstruction of human history, and the formulation of cultural invariants, such as the incest taboo and culture change, and the formulation of generalizations about "human nature", a concept which has been criticized since the 19th century by various philosophers (Hegel, Marx, structuralism, etc.). In some parts of the world ethnology has developed along independent paths of investigation and pedagogical doctrine, with cultural anthropology becoming dominant especially in the United States, and social anthropology in Great Britain. The distinction between the three terms is increasingly blurry. Ethnology has been considered an academic field since the late 18th century especially in Europe and is sometimes conceived of as any comparative study of human groups.