The Southern Grey-headed Sparrow Passer diffusus is widely distributed in southern Africa, except in southwestern Namibia and southwestern Western Cape Province of South Africa (Craig 1997). Despite it being so common, little is known of its breeding biology. Maclean (1993) stated that incubation and fledging periods are unrecorded, while Tarboton (2001) said that incubation is not recorded and nestling/fledging period is c.19 days. This paper gives some new information on the breeding biology of this species in Namibia, based on Southern Greyheaded Sparrows monitored at Zais (24°S, 16°E) in the Namib-Naukluft Park from 1986 to 1993.