More than 120,000 teachers are expected to go on strike on Tuesday over low salaries and poor working conditions, bringing teaching to a halt.
The strike will be a blow to the education sector, which has been inching ever closer to collapse over the past few years, mirroring the country's tanking economy.
This week, Zimbabwe's two largest teachers' unions, the Zimbabwe Teachers Association (Zimta) and the Progressive Teachers Union of Zimbabwe (PTUZ), said they supported the strike.
And in a joint statement on Friday, a further five unions said their members would also be joining the strike, which they said "is a pure labour matter, with no political connotations whatsoever".
The unions are the Zimbabwe Rural Teachers Union, Zimbabwe Democratic Teachers Union, Teachers Union of Zimbabwe, Zimbabwe National Educators Union and the Zimbabwe National Teachers Union.
Zimta and PTUZ said they were fed up with months of negotiations with the government that have yielded no results.
The government has refused to pay salaries in US dollars and has offered a wage adjustment of $41 for its lowest-paid worker.
Union leaders have described the government's offer as "a slap in the face". They said the offer fell far short of matching prevailing economic conditions.
Zimta CEO Sifiso Ndlovu said many of the union's members led miserable lives.
"Grounds-people [general workers] in private schools drive cars, yet our public teachers can't afford bicycles," said Ndlovu.
With a rise in the cost of living and inflation estimated at more than 200% by independent analysts, this year some teachers have been reporting to work only a few days a week, unable to afford transport costs.
The lowest-paid teacher at a government school earns a gross salary of about $500. Teachers want to be paid $1,733.
Most teachers in private schools receive between $800 and $2,000 a month.
Other perks for teachers at private schools include housing and transport allowances paid in foreign currency, 80% fees paid for their children, free accommodation for senior staff, free water and free access to the internet.
At the beginning of the new school term last month, most private schools announced fee-payment structures pegged in US dollars, relatively much higher in bond notes...