The case against McDonald's was brought by another 16-year old employee, Kasey Ramirez, who says a 23-year old shift supervisor lured her into a back storage room and put his hands around her waist and pulled her close.
"He said, 'It's okay, don't be scared, you can trust me,'" Ramirez told ABC News. "I thought his plan was to try and rape me."
She said she broke away and went to another supervisor in hysterics, who she says told her not to be so upset because everyone knew the shift supervisor, who was later fired, was a pervert.
In a statement to ABC News, the McDonald's franchise owner Michael Godlove said there is a "strict policy prohibiting any form of harassment in our restaurants."
"When Ms. Ramirez complained about the incident, which occurred in 2007, we responded promptly and took appropriate action," the statement said.
In another case, a manager at a Taco Bell restaurant in Memphis, TN pleaded guilty to raping two of his 16-year-old high school workers, one of whom became pregnant.
"The first victim worked for him about two months before she was raped. The other young lady, he attacked her on the first day that she was working for him," said Cash, the trial attorney for the Equal Employment Opportunity Commission.
In a consent decree with the EEOC, Taco Bell, while denying any wrongdoing, agreed to pay several hundred thousand dollars to the teens and to begin a training program for its managers about dealing with high school employees.
In a statement Taco Bell told ABC News, "We are outraged that this situation occurred and committed to maintaining a workplace free from harassment in all of our restaurants."
"They make enormous profits based on the work of high school kids, and that's fine," said Cash. "That can be a great working relationship in many cases. But employers that choose to use high school kids to work have a responsibility to protect these young people."
What happened to Kati Moore is not uncommon, experts say. The problem is especially prevalent in fast food restaurants where so many teenagers have their first jobs, said Dr. Susan Strauss, a consultant on corporate harassment.
"They're vulnerable, they're young, they're new to the workforce," Strauss said of the teenage employees.
One in three high school students reported unwanted sexual advances in the workplace, according to a study in Maine.
Watch "20/20" tonight at 10 p.m. for the full report.