"What happened in Steubenville was a real shock for me," she said in a statement on her website, serenawilliams.com
"I was deeply saddened. For someone to be raped, and at only 16, is such a horrible tragedy! For both families involved -- that of the rape victim and of the accused. I am currently reaching out to the girl's family to let her know that I am deeply sorry."
She termed her statements in Rolling Stone magazine "insensitive and harmful," USA Today reported.
Two players on the Steubenville, Ohio, high school football team were convicted in March of raping the girl while she was drunk. One of the players, as well as people at parties attended by the teens, also took photographs of her naked.
Williams was highly criticized for her comments about the incident.
In an article, she said, "Do you think it was fair, what they [the players] got?"
Continuing, Williams said, "She's 16, why was she that drunk where she doesn't remember? It could have been much worse. She's lucky. Obviously I don't know, maybe she wasn't a virgin, but she shouldn't have put herself in that position, unless they slipped her something, then that's different."