But some victims say the Peace Corps has continued to treat them in an insensitive way.
"There isn't a point person or an advocate or someone who is managing the case," said Casey Frazee of Cincinnati, Ohio who was sexually assaulted in South Africa in 2009. She has established a support group and website for other Peace Corps victims, First Response Action.
"No one is really looking at this because there's this over-idealized picture of the JFK Peace Corps," said Frazee.
Maggie Young of New Mexico says she decided to tell the story of her rape in South Africa in 2008 because she feels more should be known about the problem.
"It's nice to know that there are people out there who care about hearing our stories," she said of the ABC News report.
In the case of the gang rape victim, Jess Smochek, she says she was made to feel the attack was her fault because she had been walking alone shortly after 5 p.m.
"I had to list all the things that I had done wrong to cause this to happen to me," she says her counselor told her.
Other women said they were told that by having a drink or two they had invited the attacks.
"I was a risky person, and that I had in some way put myself in that situation," said Adrianna Ault Nolan, who was raped in 1998 but says she still carries the mental scars of the incident.
"I still blame myself," says Christina Holsomback of Alabama, who was raped in the country of Georgia in 2008. "Maybe I should not have had a drink or maybe we shouldn't have gone to dinner."
Victims say Peace Corps counselors are doing great damage. "Just because someone has a drink doesn't give anyone the right to violate them," said Casey Frazee. "And they need to stop telling survivors that."
"When bad things happen, you say to yourself, 'How did I bring this upon myself?' and I think, unfortunately, Peace Corps is hoping you'll think in that direction, too," said Adrianna Ault Nolan.
The Peace Corps says it is not the agency's policy to blame victims of rape and sexual assault.
"There are volunteers who have been assaulted or raped who actually do speak kindly of Peace Corps," said Hessler-Radelet.
CLICK HERE to follow the ABC News Investigative Team and Brian Ross on Facebook and join in on the discussion. Shown video of the victims' interviews, Hessler-Radelet said, "I'm deeply grieved by that. It's terrible."
She said she was surprised to hear the stories because the Peace Corps has a Special Services office designed to help victims and has recently created a task force to re-examine agency policies for dealing with sexual assault victims.
"We have a huge commitment to these women," said Hessler-Radelet. "I wasn't around before but I can control the future."
Many of the women interviewed for the ABC News 20/20 investigation said the Peace Corps needs to provide more than the limited counseling they received after they were attacked, and help to cut through bureaucratic red tape to get further treatment.
"It was too hard to navigate by myself and so I just gave up," said Jill Hoxmeier, now studying public health in New Mexico, who was sexually assaulted in the South American country of Guyana in 2007.
"If that's the case, if they need help cutting through red tape, then Peace Corps should be helping them," said Hessler-Radelet.
The victim of the gang rape, Jess Smochek, says she was given only limited counseling sessions and a one-way ticket home and still suffers from after-effects to this day, more than six years later.
"My life has changed forever," she told ABC News.
Angela M. Hill, Hanna Siegel and Chris James contributed to this report.