Basharat Dad, 32, of Eldon Road, Eastwood, Rotherham was found guilty of six counts of rape, five counts of indecent assault and one count of false imprisonment.
Appearing alongside him was his 36-year-old brother Nasar Dad, of Cranworth Road, Eastwood, Rotherham.
A jury found him guilty of rape, inciting indecency with a child and false imprisonment. He was found not guilty of one count of rape and one count of sexual intercourse with a girl under 13.
Their brother Tayab Dad, 34, of St Lawrence Road, Tinsley, Sheffield, was found guilty of one count of rape.
Mohammed Sadiq, 40, of Oxley Grove, Rotherham and Matloob Hussain, 42, of The Yews, Doncaster Road, Rotherham, were each found guilty of one count of sexual intercourse with a girl under 13.
A jury took just over six hours to reach their verdicts, which were unanimous.
During the three-week long trial at Sheffield Crown Court, the jury heard evidence from both victims that detailed sexual abuse and exploitation in the Eastwood area of Rotherham between 1999 and 2001.
Temporary Detective Chief Inspector Martin Tate, who oversaw the inquiry, said: “The court heard harrowing evidence from two very brave women whose childhoods were robbed by these men.
“They were targeted, systematically groomed and subjected to horrific sexual abuse while they were young vulnerable girls, on the cusp of their teenage years.
“No child should ever have to experience what these women have had to endure and I hope that today’s result offers them both some resolution after so many years of anguish.
“On behalf of the investigative team and the partnership agencies who have worked alongside us, I offer my thanks to those women for their support and courage over the last two years.
“I also extend our thanks and recognition to the victims’ families and the witnesses who have played their own vital roles in bringing this case before the court and obtaining these convictions.
“I want to thank the team of officers and police staff, Rotherham Council, the Crown Prosecution Service, GROW and other voluntary sector agencies who have all worked tirelessly supporting our victims, gathering evidence and preparing this prosecution case.
“As ever, we will not rest on our laurels and this case is yet a further example of our commitment to tackling child sexual exploitation and bringing these criminals before the courts.”
In a hearing at Sheffield Crown Court in February last year, 36-year-old Amjad Ali of Broad Lane, Hodthorpe, Worksop, pleaded guilty to one count of sexual intercourse with a girl under 13. He will be sentenced alongside the others convicted at Sheffield Crown Court on Thursday 2 February.
The five men convicted have been remanded in custody.