Delta Zeta sorority, which was ousted from DePauw University two weeks ago for allegedly evicting 23 members based on their weight, looks, and race, filed a federal lawsuit against the Indiana institution on Wednesday.

The sorority accuses DePauw of breach of contract, defamation, and interfering with the national organization’s business relationships. Delta Zeta is asking to be permitted back on the campus, and is seeking a public apology from DePauw and an acknowledgement that it did not discriminate against its members based on race or appearance. In a statement on its Web site, Delta Zeta also accuses the university of inflicting “significant harm on many of the student members of the sorority by deliberately exposing them to national ridicule.”

In December, nearly two-thirds of the chapter’s 35 members were told they had been recommended for “alumna status” and were asked to leave the sorority house. A media furor erupted in late February after The New York Times reported on those evictions, saying the sorority had dropped all of the chapter’s members who were overweight, and had kept only those who were conventionally pretty or popular.

Kevin O’Neill, a lawyer advising the sorority, says that the DePauw chapter’s membership had been dwindling, and that Delta Zeta was acting on the university’s advice when it conducted the membership review. Delta Zeta chose to retain only those members who demonstrated commitment to actively recruiting new members, he told The Chronicle.

He added that, before asking the 23 women to leave, the sorority had submitted a list of their names to DePauw so that the university could provide the women with alternative housing. “Had the university had a problem with that, that would have been the time to lodge an objection,” Mr. O’Neill said. “No objection was lodged at any point in the process.”

The university disputes Delta Zeta’s assertions. “We believe that this lawsuit completely lacks merit,” a university spokesman, Ken Owen, said in a written statement. —Paula Wasley