(CNN) For the second time in four months, South Carolina teachers are fed up and ready to rally.
Hundreds of educators plan to protest at the state capitol on May 1 at an event called "#AllOutMay1."
"Those that care about public education in South Carolina demand better teacher pay, smaller class size, removing other duties as assigned from teacher contracts, less testing and a pledge from our legislature that they will say no to for-profit charter schools and educational savings accounts," the SC for Ed advocacy group said.
It's not clear how many schools, if any, will be forced to close next Wednesday. As of Tuesday afternoon, 355 people had registered on Facebook for the protest.
"We know it is a sacrifice for educators to be out of their classrooms," SC for Ed said. "However, not participating in this event will only allow the cycle of detrimental education policy to continue in our state."
Next week's protest follows a similar event on January 29, in which some South Carolina teachers took personal days off work to meet with lawmakers for a "Money Matters Lobby Day."
Teachers called for a 10% across-the-board salary increase to get closer to the national average. As of 2017, South Carolina ranked 38th in teacher pay, with an average salary of about $50,000, according to data from the National Education Association.
SC for ED said teachers "are leaving the profession because their salaries are too meager to provide a reasonable standard of living for themselves and their families."
The group is lobbying for legislation that would prohibit retaliation against teachers for making public policy comments and reduce the amount of standardized testing.
Some lawmakers have touted House Bill 3759 as a way to improve education and boost teacher salaries. If enacted, the minimum salary for entry-level teachers would jump from $32,000 to $35,000.
But SC for ED said it had concerns about the bill, including a part that would allow high-performing schools to hire more noncertified teachers, as long as they don't make up more than 25% of the teaching staff.
The state Senate's version of the upcoming budget would give teachers raises of at least 4%, CNN affiliate WBTW said. But protest organizers say that's not enough to make them stand down.
"The 4% raise is a positive step forward, but it's just one step," SC for Ed said. "Join us as we march for the future."