Hope Solo,the World Cup winner, 36, says the incident happened at the 2013 Ballon d’Or awards, before she went on stage to present an award.
In an interview with a Portugese newspaper Expresso, Solo said: “I had Sepp Blatter grab my ass.”
Blatter has denied the incident took place, with his spokesman telling BBC Sport: “This allegation is ridiculous.”
Solo, when asked why she has not spoken out on the incident before, added: “I was nervous for the presentation. It was the Ballon d’Or I was presenting.
“After that I didn’t see him and that was kind of bad. I didn’t get to tell him directly ‘don’t ever touch me’. That’s the way I’ve always handled things – directly.”
A growing number of public figures have been accused of sexual harassment in recent weeks, sparked by multiple women speaking out against the Hollywood mogul Harvey Weinstein.
Solo, says the issue is “rampant” in women’s football.
“I’ve seen it throughout my entire career,” she said. “It’s not just in Hollywood.
“For years, in the past, female players date and end up marrying their college coaches, which obviously a coach should not be doing, especially with a young player.
“I’ve seen it not just with coaches, I’ve seen it with trainers, doctors, and our press officers. I’ve seen it among players in the locker room. I don’t know why more players don’t speak out against it.”