Ostrów Pieckowski [ˈɔstruf pjɛt͡sˈkɔfski] is a settlement in the administrative district of Gmina Piecki, within Mrągowo County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately 3 kilometres (2 mi) north of Piecki, 12 km (7 mi) south of Mrągowo, and 55 km (34 mi) east of the regional capital Olsztyn.