Saterland Frisian (East Frisian; Fräisk or Seeltersk) is a Frisian language in the German Ostfriesland region , spoken today only in a small area know as Saterland. It is closely related to West Lauwers Frisian and was formerly (i.e. until the 15th century) spoken in the whole of Ostfriesland, as well as in what is now the Dutch province of Groningen. The language referred to today as Ostfriesisch in German is a Low Saxon dialect, though its Frisian substrate is still evident. Frisian remained in Saterland because it used to be a little accessible island in a swampy area.

Today estimates of the number of speakers vary slightly; an estimated 2,000 people might speak the language well, of which slightly less than a half are native speakers. The vast majority of all native speakers are found among the elder generation; Saterlandic thus is a seriously endangered language. It might, however, no longer be moribund, since several reports suggest the number of acquired speakers is raising among the younger generation and some of them are said to raise their children in Saterlandic.