Studnica lake (Polish: jezioro Studnica, pronounced [jɛˈʑɔrɔ studˈɲit͡sa]) is a lake located in the Gwda Valley District, in the north-west part of Poland. It is 24.9 m (82 ft) deep, 2.2 km (1.4 mi) long and 0.8 km (0.50 mi) wide. Studnica lake is also the source of Gwda river.

There are four different Studnica lakes in Poland.