Jeziernik [jɛˈʑɛrnik] is a village in the administrative district of Gmina Ostaszewo, within Nowy Dwór Gdański County, Pomeranian Voivodeship, in northern Poland. It lies approximately 3 kilometres (2 mi) south-east of Ostaszewo, 9 km (6 mi) west of Nowy Dwór Gdański, and 29 km (18 mi) south-east of the regional capital Gdańsk.

Before 1772 the area was part of Kingdom of Poland, 1772-1919 Prussia and Germany, 1920-1939 Free City of Danzig, 1939 - February 1945 Nazi Germany. For the history of the region, see History of Pomerania.