Świętajno [ɕfjɛnˈtai̯nɔ] (German: Schwentainen, 1938-45 Altenkirchen) is a village in Olecko County, Warmian-Masurian Voivodeship, in northern Poland. It is the seat of the gmina (administrative district) called Gmina Świętajno. It lies approximately 13 kilometres (8 mi) west of Olecko and 122 km (76 mi) east of the regional capital Olsztyn.
Before 1945 the area was part of Germany (East Prussia).
The village has a population of 1,600.
Coordinates: 54°0′5″N 22°19′3″E / 54.00139°N 22.31750°E