Asking for and sending nude photos was most prevalent among white non-Hispanics and black teens, the study found.
White, black and Hispanic students each accounted for about 30 percent of study participants. All respondents were sophomores or juniors.
More older teens reported "sexting," and 16- to 17-year- olds were most likely to have been asked to send a naked photo.
"There is a very strong age effect. The older the person, the more likely," said Donald Strassberg, a University of Utah psychology professor who researched sexting in a study published earlier this year.
In Strassberg's study, which appeared in the Archives of Sexual Behavior, about 20 percent of teens at a private school reported sending text message photos of genitals or breasts. Another telephone survey published in the journal Pediatrics put the number at as little as 2.5 percent.
"Different samples come up with different results," Strassberg said. "Part of it depends on the specific question that was asked."
The growing number of sexting studies in the result of media attention that has sparked researcher's curiosity, Strassberg said.
"I think it just became apparent to more researchers that, hey, we don't really have a good idea of how prevalent this is," he said.