New Zealander social anthropologist best known for his research on the Maori and other peoples of Oceania and Southeast Asia.

Firth began his studies at Auckland University College in his native New Zealand and then continued at the London School of Economics, from which he obtained his doctorate. A brief affiliation with the University of Sydney (1929–32) was thereafter the only break in Firth's association with the London School of Economics; he became a full professor there in 1944 and, in 1968, professor emeritus. He was knighted in 1973.

Firth was strongly influenced by Bronisław Malinowski (Malinowski, Bronisław) and edited Man and Culture: An Evaluation of the Work of Bronislaw Malinowski (1957), considered one of the best works about this influential anthropologist. Firth's first major contribution to anthropology was Primitive Economics of the New Zealand Maori (1929). The economic organization of primitive societies continued to be one of Firth's primary interests, as indicated by his works on the Kauri gum industry and the fishing industry of Malaysia. Among his other chief interests were social structure and religion, especially of the Tikopia of the Solomon Islands, and the anthropological treatment of symbols.

The work of Firth's that is widest in scope is his influential Human Types: An Introduction to Social Anthropology (1938). His other notable works are We, the Tikopia (1936), Essays on Social Organization and Values (1964), Malay Fishermen: Their Peasant Economy (1966), Rank and Religion in Tikopia (1970), and Symbols: Public and Private (1973).