A 26-year-old woman has been arrested after killing her boyfriend in a domestic dispute in Orange Farm on Saturday, said Gauteng police.

"The boyfriend had a knife. Apparently, the girl in self-defence, after the boyfriend stabbed her, took the knife and stabbed the boyfriend," said Captain Johannes Motsiri.

The man, age 35, died on the scene.

Motsiri said the woman was arrested for murder shortly after the incident at 5.30pm.

She will appear in Vereeniging Magistrates' court on Monday.