Ngũgĩ wa Thiong'o (Gikuyu pronunciation: [ŋɡoɣe wa ðiɔŋɔ]; born 5 January 1938) is a Kenyan writer, formerly working in English and now working in Gikuyu. His work includes novels, plays, short stories, and essays, ranging from literary and social criticism to children's literature. He is the founder and editor of the Gikuyu-language journal Mũtĩiri.

In 1977, Ngũgĩ embarked upon a novel form of theatre in his native Kenya that sought to liberate the theatrical process from what he held to be "the general bourgeois education system", by encouraging spontaneity and audience participation in the performances. His project sought to "demystify" the theatrical process, and to avoid the "process of alienation [that] produces a gallery of active stars and an undifferentiated mass of grateful admirers" which, according to Ngũgĩ, encourages passivity in "ordinary people".Although Ngaahika Ndeenda was a commercial success, it was shut down by the authoritarian Kenyan regime six weeks after its opening. Ngũgĩ was subsequently imprisoned for over a year.

Adopted as an Amnesty International prisoner of conscience, the artist was released from prison, and fled Kenya. In the United States, he taught at Yale University for some years, and has since also taught at New York University, with a dual professorship in Comparative Literature and Performance Studies, and the University of California, Irvine. Ngũgĩ has frequently been regarded as a likely candidate for the Nobel Prize in Literature. His son is the author Mũkoma wa Ngũgĩ.