A jury at Guildford Crown Court found the 25-year-old singer spat at a man who stepped in to protect the two 19-year-olds with whom Dappy had started arguing after they rejected his advances.
The trial was told Dappy became angry, sparking the brawl, after the teenagers "dissed him" and called him boring.
The jury, made up of eight men and four women, took eight-and-a-half hours to find Dappy guilty of affray and assault by beating.
Co-defendant Kieran Vassell, 25, of Hammersmith, west London, was also found guilty of affray, while Kalonji Stewart, 32, of Harborne, Birmingham, was found not guilty of the same offence.
Judge Neil Stewart adjourned proceedings for pre-sentence reports to be prepared on Dappy and Vassell.
The case was adjourned for sentencing on February 15 and the pair were released on unconditional bail until then.
Dappy faces a maximum sentence of three years' imprisonment for affray and six months for assault by beating.
The court heard that Dappy was convicted of assault by beating in 2008 after spitting at two women.
The nine-day trial heard Dappy, charged under his real name of Costadinos Contostavlos, had been out on February 27 last year celebrating the release of his single Rockstar featuring Queen guitarist Brian May.
After spending the night in the VIP area of the Casino nightclub in Guildford, Surrey, the group headed back in three cars to the recording studios in Godalming where Dappy was working on his debut solo album. The group stopped at the Shell garage in Guildford, at about 3.30am, where the violence erupted.