Male Tawny Grassbirds are more obvious during breeding season when they sing in conspicuous display flights or from exposed perches. Breeding males perform their distinctive but brief display flights, mostly in early morning or late afternoon, singing in flight above vegetation, with wings quivering and only partly spread and long tail trailing and drooping down or spread.
The nest is a deep cup, slightly narrowed at rim, and is made of coarse dry blades of grass or rushes, neatly lined with finer grass and sometimes with horse or cow hair. These nests are usually well concealed in rushes, sedges, tussocks of grass or tangles of other vegetation.
Incubation is done by females only.