Lohsa (German) or Łaz (Upper Sorbian, pronounced [ˈwas]) is a municipality in the district of Bautzen, in Saxony, in eastern Germany.

The municipality is part of the recognized Sorbian settlement area in Saxony.

Upper Sorbian has an official status next to German, all villages bear names in both languages.

To the east of the municipality runs the B 156, to the west the B 96, via which the B 97 to the northwest can be reached.

Lohsa is connected to the Niesky-Hoyerswerda(-Falkenberg (Elster)-Roßlau (Elbe)) railway line by a demand stop.