Whatever the medium, more girls were victims: 52 percent of girls said they had been harassed in person, and 36 percent online, compared with 35 percent of boys who were harassed in person and 24 percent online.

“I was called a whore because I have many friends that are boys,” one ninth-grade girl was quoted as saying. An eighth-grade boy, meanwhile, reported, “They spread rumors I was gay because I played on the basketball team.”

The study asked students to reflect on the 2010-11 school year in an attempt to capture the prevalence of sexual harassment, the effects it has on the harassed and the reasons the harassers engage in the behavior. It also questioned students about preventive measures. Coming amid increased attention to bullying and cyber-bullying, the report aimed to highlight the damaging effects of inappropriate sexual comments, online rumors or lurid Facebook posts.

“Bullying is getting a lot of attention,” said Holly Kearl, an author of the report and program manager of the university association’s Advocacy Fund. “We don’t want schools to forget about sexual harassment” and not talk about it, she said. Ms. Kearl said some schools that talk to students about sexual harassment and how to respond to it have been successful in reducing it. “We want to encourage schools to know what Title IX is,” she said, referring to the federal law that prohibits discrimination based on gender in schools, “to have a coordinator and to publicize it.”

The report documents many forms of harassment. The most common was unwelcome sexual comments, gestures or jokes, which was experienced by 46 percent of girls and 22 percent of boys. Separately, 13 percent of girls reported being touched in an unwelcome way, compared with 3 percent of boys; 3.5 percent of girls said they were forced to do something sexual, as did 0.2 percent of boys. About 18 percent of both boys and girls reported being called gay or lesbian in a negative way.