Trnovačko Lake (Serbian: Трновачко језеро, romanized: Trnovačko jezero) is a lake in northern Montenegro, best known for its heart-like shape.

Located at an altitude of 1517 metres, it is popular with local summer campers.

[1][2] The lake is drained from the Maglić, the Volujak and the Bioč mountain ranges.

The north side of the lake which is open has the wooded Vratnice.

[3][4] The plan is to form a national park within the borders of Montenegro, which should protect rest of the mountain range of Magilć-Volujak-Bioč and Trnovačko Lake.