More than 100 union workers at a Lawrence-based nonprofit serving people with disabilities agreed to a new contract Saturday, averting a second strike in less than a month, according to SEIU Local 509.

The one-year contract agreed to by the union and managers at CLASS Inc. includes a 60-cent hourly wage increase, provides for new signing bonuses, and allows workers to cash out unused vacation days, Local 509 president Peter MacKinnon said.

“For this group, this is both a victory, but not the end,’’ MacKinnon said in an interview Saturday. “Our members at CLASS are some of the lowest paid in all of the 509, but this is a step in the right direction.’’

The deal, which was reached after marathon negotiations that started Friday night, covers about 115 workers at CLASS Inc. facilities in Lawrence and Wilmington. Workers provide a range of services, including job training and transportation to people with autism and other disabilities.

The union had said workers would go on an open-ended strike starting Monday if a new contract to raise wages and improve working conditions was not reached.

Earlier this month, workers went on strike from July 9-13 to protest contract talks that involved a federal mediator. Workers who picketed outside CLASS building on Parker Street drew strong support, including from Lawrence Mayor Daniel Rivera and Democratic candidates for governor Jay Gonzalez and Bob Massie.

The prospect of a second strike might have added pressure for CLASS to reach agreement with the union, MacKinnon said.

In a statement Saturday, Alfred J. Frugoli, president and chief executive at CLASS, acknowledged the “difficult and lengthy negotiations’’ for the company and union. But he thanked negotiators on both sides, as well as federal mediators who assisted both sides.

“Thanks to the perseverance and hard work of the negotiating teams, a second work stoppage has been averted at this vital human services agency and program operations will resume on Monday without disruption,’’ Frugoli said.

The agreement will enable the agency to provide “valuable direct-care’’ to people with disabilities, while keeping wages in check with state reimbursement rates, Frugoli said.

“We can only pay what is afforded in those rates,’’ he said.

Still, even with the wage increase, most workers at the agency will still earn less than $15 per hour, according to MacKinnon.

“It’s probably the most important work, and it’s the worst paying,’’ MacKinnon said.

Marek Mazurek can be reached at marek.mazurek@globe.com