Chicago Public Schools staff and Chicago Park District workers are expected to delivery strike notices to Mayor Lori Lightfoot Tuesday.
The CPS staff voted to authorize a strike in July and park workers approved the move in a vote last week.
The earliest date CPS staff could go on strike would be Oct. 17. Chicago Park District workers can strike as early as Oct. 9.
"While there has been some positive developments in recent negotiations, Mayor Lightfoot and the city have still failed to offer a contract that fully addresses the economic concerns and working conditions of school staff and park workers," the groups said in a joint statement. "Most importantly, the latest offers does not ensure the clean, safe schools and parks that workers are demanding and it does not make sure that students in special education receive the care and instruction they deserve."
The move comes as negotiations resume with the Chicago Teachers Union Tuesday.
Union leaders began bargaining sessions with the Chicago Board of Education last week in an effort to keep teachers from walking off their jobs. The union is calling for more staffing and a cap in class sizes.
"It's almost as if they're daring us to strike over these issues," CTU President Jesse Sharkey said in a press conference Friday.
The union announced members voted to authorize a strike Thursday night, setting the stage for more than 25,000 teachers and staff to walk off the job in the nation's third-largest school district.
"This is a clear message to the mayor and the Board of Education to address critical needs in our schools," Sharkey said in announcing the vote.
Chicago Public Schools officials say their latest contract offer included a 16% raise, which would put the average teacher salary at nearly $100,000 within the next five years.
But CTU officials say the potential strike is about more than money: they want improvements in areas related to class size, staffing shortages, and provisions related to safety and security of students in areas surrounding schools.
Union leaders have said they want promises made by then-candidate and now-Mayor Lori Lightfoot in writing, like more social workers, school nurses and librarians, as well as maximum class sizes.
Lightfoot and Chicago Public Schools CEO Dr. Janice K. Jackson released a joint statement on Thursday night.
"As a city, we make promises to our children, including ensuring that every single student receives a high-quality education that allows them to live up to their full potential and fulfill their dreams," the statement read, in part. "For the last several months, we have engaged with teachers in a good faith effort to create an inclusive process that listens to their concerns and ideas on how to improve our schools, input which is now reflected in the historic offer that supports our shared progressive values and desire for every child to be equally prepared for success.
"We are committed to doing everything we can to finalize a deal that is sustainable for all Chicagoans and for our city's future, that respects our teachers, and continues our students' record-breaking success for years to come," they added.