Kojdy [ˈkɔi̯dɨ] is a city in the administrative district of Gmina Łukta, within Ostróda County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately 9 kilometres (6 mi) north-east of Łukta, 23 km (14 mi) north-east of Ostróda, and 25 km (16 mi) west of the regional capital Olsztyn.