In the suit, filed Tuesday in the Superior Court of California in Los Angeles, Judy Huth of Riverside, Calif., alleges that in 1974, when she was 15, she and a friend, who was 16 at the time, met Cosby where a movie was being filmed in Los Angeles.
According to the suit, he allegedly invited them to meet him at his tennis club the following Saturday. When they arrived, Cosby allegedly brought them to a house, where he gave them alcohol.
He allegedly then took them to the Playboy Mansion, where, in a bedroom suite, he "proceeded to sexually molest her by attempting to put his hand down her pants and taking her hand and performing a sex act on himself without her consent," the suit says.
"This traumatic incident, at such a tender age, has caused psychological damage and mental anguish for [Huth] that has caused significant problems throughout her life," the suit says.
The suit seeks unspecified compensatory, punitive and exemplary damages.
ABC News has tried to reach Cosby's representatives for comment on the suit, but they could not be reached.
More than a dozen women have come forward in recent weeks, accusing the comedian of drugging and sexually assaulting them. Cosby, 77, has never been criminally charged stemming from any of the sex-abuse allegations, many of which date back to the 1970s and 1980s.
A statement released last month by Cosby's attorney, Marty Singer, called the recent allegations against Cosby "unsubstantiated, fantastical stories."
As the accusations have grown, Cosby has cancelled a number of stand-up shows and networks like TV Land have pulled reruns of "The Cosby Show." On Monday he announced he was resigning from the Board of Trustees at Temple University, his alma mater.