A process for preparing an organosilicon compound which contains Bunte salt groups, which comprises reacting at least one silane of the general formula R3 d R5 e Si(OR4)4-d-e (II) and/or a partial hydrolysate thereof, in which R3 is a hydrogen atom or a monovalent organic radical, R4 is a hydrogen atom or a monovalent organic radical, R5 is the radical --Q'Y, where Q' is a divalent organic