Vassar College, one of the first institutions of higher learning for women in the United States, prides itself for being a pioneer in women’s education and deeply committed to equality between the sexes.

And yet, Vassar, a liberal arts college in Poughkeepsie, N. Y., where tuition this year is $67,000, has systematically paid its female professors less than their male counterparts for the past two decades, according to a recent federal lawsuit.

The suit, filed last month by five former or current tenured faculty members, has roiled the left-leaning campus with allegations of unequal pay, delayed promotions for female professors and a discriminatory performance-evaluation system.

Hundreds of students rallied outside a faculty meeting last week to demand that female professors be paid the same as men. On a campus where the promise of gender equality is a draw for students seeking a college culture steeped in diversity and equity, many students interviewed said the issues raised by the suit had left them feeling betrayed.

Solaar KirkDacker, a senior who helped to organize the protest, said she was “enraged” by the allegations.

“They really capitalize off of this idea of promoting the advancement of women in higher education, and that was something that really attracted me,” she said. “I felt very cheated by Vassar.”

Adopting the college’s current fund-raising slogan, “Fearlessly Consequential,” several students said they had decided to be “fearlessly consequential” by standing up for the values Vassar says it upholds.

“It just feels like a culmination of my education here,” Charlie Kanner, a recent graduate and rally organizer, said. “Being able to use all of the skills that our professors have given us to support them feels really, really special.”

In a display of solidarity, dozens of professors wore white to the faculty meeting. As students cheered outside, some educators arriving for the meeting became visibly emotional. About 35 full and retired Vassar professors have signed a letter in support of the suit.

Officials at Vassar, which became coeducational in 1969, have issued several statements defending the college but have declined interview requests.

“Vassar College has been working diligently and continuously on the issue of pay equity with a group of professors since January 2019,” Anthony J. Friscia, the board of trustees’ chair, wrote in a statement posted on the school’s website after the suit was filed. “Vassar believes it pays its faculty fairly and equitably and has complied with the law, and it would like to resolve this issue.”

Vassar’s president, Elizabeth Bradley, said in a letter to the editor published in the student newspaper, The Miscellany News, that she knew that the allegations might “leave many people in the community feeling confused, angry or hurt.”

However, she wrote, “the faculty members who brought this lawsuit have a different understanding of the relevant facts and law that is at issue in this dispute.”

Last week, Ms. Bradley said in a statement to The New York Times that Vassar had agreed to allow a faculty committee to hire an independent compensation-analysis firm to examine salaries, and would act on the findings.

The suit’s plaintiffs cite salary data released publicly by the college, which they say shows Vassar administrators have known about the pay gap for years.

In the 2003-04 academic year, female full professors earned about 7 percent, or $7,770, less on average than their male counterparts, according to the data, which was published in the Chronicle of Higher Education.

The gap has widened since, the data shows. During the 2021-2022 academic year, male full professors earned $153,238 on average — about 10 percent, or $13,900, more than women of the same academic rank.

Because women are often hired at lower salaries, and raises are usually given as a percentage increase, the disparity has been most pronounced among the longest-serving professors, the suit says.

Vassar officials have not disputed the data but say the disparities are tied to differences in seniority, academic discipline and peer evaluations.

Not all Vassar professors are protesting. Sarah Pearlman, an economics professor who teaches about gender issues, said she wanted more information about salaries before drawing conclusions.

“I really would like that information,” she said, “and unfortunately I get the sense that we can’t get it.”

Other colleges have come under scrutiny for wage gaps in recent years. Princeton, for instance, agreed to pay nearly $1 million to 106 female professors in 2020 after a federal pay-equity inquiry.

The gender pay gap at Vassar is smaller than the average in academia: Female professors in the United States earn 17.7 percent less than their male peers, according to data published by the American Association of University Professors.

Jessica Stender, the deputy legal director at Equal Rights Advocates and a lawyer for the Vassar plaintiffs, said she was surprised the college had not done more to address the pay gap given its status as a standard-bearer of women’s education and one of the Seven Sisters consortium of historically women’s colleges.

That such problems could exist at Vassar, she said, “is really indicative of how deep and how pervasive pay discrimination problems are in our society.”