Dappy - real name Costadinos Contostavlos - was present at Guildford Crown Court on Friday as the verdict was read out.
The singer was arrested on 12 March last year following the incident at a Shell garage in Woodbridge Road, Guildford, Surrey, in the early hours of 28 February.
Grace Cochran and Serena Burton were allegedly spat at by the star after he attempted to chat them up, before an altercation on the forecourt with bystander David Jenkins, who had intervened along with three other men.
Dappy previously pleaded not guilty to two counts of common assault on the girls, one count of assaulting Jenkins by beating - which involved him spitting at him - and one charge of affray.
He was cleared of the charges involving Cochran and Burton, but was found guilty of the other two offences.