Jill Campbell and her husband, Gary, compiled evidence in 1999 that helped convict the director of an Ethiopian orphanage that the Swiss charity Terre Des Hommes-Lausanne used to run.
The charity acknowledged the abuse took place, but brought a successful defamation case against the Campbells for their claims that the charity's senior staff covered up the scandal.
The Swiss charity asked the court not to sentence Jill Campbell because her husband, Gary, had made a public apology last month, said Seleshi Ketsela, a lawyer who represented her in the case.
"The case is closed. ... They said one (apology) is enough," Seleshi told The Associated Press.
Jill Campbell was convicted Wednesday and had faced up to six months in prison. She said that she was relieved by the outcome, but was unhappy that the charity had not formally apologized to the victims or financially compensated them.
"I regret nothing and I apologize for nothing as well because we did nothing wrong," she told journalists.
Gary Campbell issued a public apology for the comments last month, then said he did so only because nobody would be able to care for the couple's children if they both went to jail.