Wiggins, who won the 2012 Tour de France and three Olympic gold medals, claimed he was just 13 when treated by the unnamed trainer.
He said he couldn’t speak at the time due to a difficult relationship with his stepfather.
The 41-year-old has previously opened up about suffering from depression and having a difficult childhood.
“I was groomed by a trainer when I was younger – I was around 13 – and I never fully came to terms with that,” Wiggins told Men’s Health UK magazine.
Asked if he had been groomed sexually, Wiggins added: “Yeah. It all got to me as an adult. I buried it. My stepdad was pretty abusive to me, he called me a fag [homosexual] for wearing Lycra and stuff, so I didn’t think I could tell him.
“I was so lonely. I just wanted to get out of the environment. I became so insular. I was quite a weird teenager in a lot of ways and I think riding the bike stemmed from adversity.”
Wiggins reached the pinnacle of his sport in 2012, when he became Britain’s first Tour de France winner before claiming Olympic gold in the time trial in London days later.
However, he said he had spent much of his life trying to figure out his relationship with his father, Australian cyclist Gary Wiggins, who left the family when Bradley was young and died in 2008 following of a fight at a house party.
“It was definitely because of my dad. I never got any answers when he was murdered in 2008. He left us when I was little so I first met him when I I was 18,” he said.
“We rekindled some sort of relationship, but we didn’t speak for the last two years before he was murdered.
“He was my hero. I wanted to prove myself to him. He was a good cyclist, he could have been really good, but it was a wasted talent.
“He was an alcoholic, a manic-depressive, quite violent and he took a lot of amphetamines and [sports] drugs at the time.”
British Cycling has contacted the retired rider to offer their support.
“We are deeply concerned by the matter raised by Sir Bradley Wiggins and our backup team contacted him today to offer him our full support,” the organization said in a statement.
“We encourage anyone who has experienced abuse or is concerned about the welfare of others – regardless of when the incident occurred – to utilize the support offered by both our trained team British Cycling and the NSPCC’s dedicated helpline, which in turn helps us to ensure that our sport is a safe and welcoming place for all.”