Jamielnik [jaˈmjɛlnik] is a village in the administrative district of Gmina Lidzbark, within Działdowo County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately 4 kilometres (2 mi) south-west of Lidzbark, 26 km (16 mi) west of Działdowo, and 77 km (48 mi) south-west of the regional capital Olsztyn.