Tetun is an Austronesian language spoken in the central and eastern parts of the island of Timor. It is widely used throughout East Timor as a lingua franca, in addition to being a first language in some regions. this description comprises a detailed grammar of the conservative Fehan dialect, spoken near the south coast of West Timor. It is primarily based on a corpus of spoken and written texts, supplemented by elicitation and daily exposure to the language. The description covers a phonology and morphology, as well as phrase, clause and sentence-level syntax. This is the first detailed grammar of any of the dozen or so Austronesian language spoken in central and eastern Timor. It complements earlier Dutch descriptions of Dawan and Roti, spoken in West Timor and the neighbouring island of Roti respectively.