Zielonka [ʑɛˈlɔnka] is a town in Wołomin County, Masovian Voivodeship, Poland, with 17,398 inhabitants (2013).

Zielonka borders Warsaw and several other towns of the Warsaw metropolitan area: Ząbki and Marki in the west, Kobyłka in the north, and Sulejówek in the south.

In August 1920, the Battle of Ossów was fought nearby, as part of the Battle of Warsaw in which the Poles were victorious and repulsed the Soviet invasion.

Within the town limits, near the village of Ossów, there is a cemetery of the fallen Polish soldiers with a chapel of Our Lady of Victory.

This Wołomin County location article is a stub.