Zajączkowo [zajɔnt͡ʂˈkɔvɔ] is a village in the administrative district of Gmina Milejewo, within Elbląg County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately 3 kilometres (2 mi) north-east of Milejewo, 19 km (12 mi) north-east of Elbląg, and 80 km (50 mi) north-west of the regional capital Olsztyn.

Before 1772 the area was part of the Kingdom of Poland; from 1772 to 1945, Prussia and Germany (East Prussia).