Świętajno [ɕfjɛnˈtai̯nɔ] (German: Altkirchen; before 1938: Schwentainen) is a village in Szczytno County, Warmian-Masurian Voivodeship, in northern Poland. It is the seat of the gmina (administrative district) called Gmina Świętajno. It lies approximately 16 kilometres (10 mi) east of Szczytno and 54 km (34 mi) south-east of the regional capital Olsztyn.
Before 1945 the area was part of Germany (East Prussia). In the East Prussian plebiscite of 1920 1,253 inhabitants voted to remain in Germany, none for Poland. Following World War II the native German populace was expelled and replaced by Poles.
The village has a population of 2,000.
Coordinates: 53°33′52″N 21°13′2″E / 53.56444°N 21.21722°E