The Boston Teachers Union, expressing frustration that contract negotiations have dragged on for more than a year, accused the school system and the city Tuesday of not taking the talks seriously because the union is made up mostly of women.

“Both the School Department and the city have, frankly, treated us poorly and disrespectfully,’’ Richard Stutman, president of the Boston Teachers Union, wrote in his weekly newsletter, noting that 76 percent of the city’s teaching force consists of women.

“We have little doubt that, were the BTU a workforce 76 percent male, we’d have settled the contract by now,’’ Stutman said.

The city declined to directly address the union’s charges of gender discrimination.

“Conversations are ongoing between representatives of the City of Boston and Boston Teachers Union and we hope for a swift resolution that best serves all students,’’ Nicole Caravella, press secretary for Mayor Martin J. Walsh, said in a statement.

The School Department did not comment.

Stutman’s assertions came one day before legions of women are expected to take part in Wednesday’s International Women’s Strike — A Day Without a Woman — to draw attention to an array of issues, including the need for equal pay, free child care, paid family leave, and ending racism.

The Boston Teachers Union is not encouraging members to skip work Wednesday because it doesn’t want any of the school system’s 56,000 students to miss out on a day of learning. That decision keeps within the spirit of a state law that forbids teacher unions from striking.

But the teachers union is cosponsoring an A Day Without a Woman rally Wednesday evening.

The union also has scheduled a “walk in’’ Friday morning before classes begin at each of the system’s 125 schools to raise public awareness about the “poor treatment our workforce has received.’’

The union has been in negotiations for the last 14 months to replace a contract that expired last August. Stutman, in his newsletter, said those talks have stalled and the school system has been unresponsive to requests to meet again.

In an interview, Stutman said gender discrimination in the talks often surfaces around pay.

“We haven’t been offered what at least one other city union has settled for,’’ said Stutman, who is hoping to have the contract settled before he retires in June. “I think it is a purposeful undervaluing of our work every day.’’

Stutman didn’t mention the other union by name, but Walsh announced last month the city had settled a $68 million contract with the patrolman’s union in “record time.’’ That four-year deal, which still requires City Council approval, would give patrol officers an annual 2 percent pay raise.

It is difficult to compare the pay of patrolmen and teachers because a number of factors can boost their base salaries, experts say. Police have much greater opportunities to boost their annual pay by working overtime and paid details, while teachers can receive stipends for working extended school days and summer sessions or earning advanced degrees.

The average patrolman’s salary — excluding overtime and paid details — is $80,000 and the average teacher pay is $90,000, excluding stipends, according to data from the Police and School departments.

The School Department has long made the case that Boston teachers are well paid in comparison to most of their Massachusetts peers and those nationwide. According to the most recent state data for all school systems, the average teacher salary in Boston ranked 17th for the 2014-15 school year.

This is at least the second time the teachers union has accused the school system of gender discrimination in the contract talks. A few months after negotiations began last January, the union criticized the district for seeking to end the practice of guaranteeing that teachers whose maternity leaves last more than six months can return to their same job assignment.

James Vaznis can be reached at james.vaznis@globe.com. Follow him on Twitter @globevaznis.