Sapuan (autonym Sapuar) is an endangered West Bahnaric (Mon-Khmer) language spoken by the population of a single village, Ban Sapuan, about 40 kms north of Attapeu (Lao PDR). Other than a short wordlist collected early this century, no other descriptions of Sapuan are known. The present sketch grammar is prepared on the basis of the authors' recent fieldwork. Sapuan phonology and syntax are discussed and short glossed texts and a lexicon are provided. The work is illustrated with a map of the South Bahnaric area and some line drawings of village scenes.