Łajsy [ˈwai̯sɨ] is a village in the administrative district of Gmina Gietrzwałd, within Olsztyn County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately 4 kilometres (2 mi) south-east of Gietrzwałd and 16 km (10 mi) south-west of the regional capital Olsztyn.

Before 1772 the area was part of Kingdom of Poland, and in 1772–1945 it belonged to Prussia and Germany (East Prussia).