Olszanka [ɔlˈʂaŋka] is a village in the administrative district of Gmina Sejny, within Sejny County, Podlaskie Voivodeship, in north-eastern Poland, close to the border with Lithuania. It lies approximately 3 kilometres (2 mi) south-east of Sejny and 111 km (69 mi) north of the regional capital Białystok.