Ambjørg Sælthun (born 27 July 1922 in Ål) is a Norwegian politician for the Centre Party.
She was elected to the Norwegian Parliament from Sogn og Fjordane in 1973, and was re-elected on two occasions. She had previously served as a deputy representative during the term 1969–1973. From 1972 to 1973 she moved up as a regular representative, filling in for John Austrheim who was appointed to the cabinet Korvald.
On the local level he was a member of Lærdal municipal council from 1971 to 1975. She was a member of the central party board from 1976 to 1982, and chaired the Centre Party Women's Association (Senterkvinnene) during the same period.
Outside of politics she was a farmer, having also worked briefly as a nurse. She was active in the Norwegian Agrarian Association, in Christian organizations, and was a member of the board of the publishing house Det Norske Samlaget from 1979 to 1983.