The public-sector union, Unison, the Transport and General Workers' Union and the GMB have all pledged support for a nationwide campaign being spearheaded by the National Union of Teachers.
John Monks, general secretary of the TUC, is to speak at a rally being organised later this month which aims to draw together protest groups from across the country.
Free coaches and trains are being laid on by the NUT for what its president Carole Regan calls the "biggest and most united demonstration for education this country has ever seen".
Doug McAvoy, NUT general secretary, said: "Our aim is to make sure the Government is left in no doubt about the depth of concern at the desperate underfunding of our schools. Schools faced a massive Pounds 752 million shortfall in their funding this year. Teachers' jobs have been lost and class sizes have increased for the sixth year running.
"School buildings continue to crumble, pupils are denied books and equipment and teachers and parents spend hours trying to raise funds to ease the problems."
The rally and a march in London form a national "day out for education" designed to influence Government in the run-up to its November public-spending announcement which will determine whether schools face another round of cuts. The hoardings campaign is costing the NUT Pounds 158,000.
The rally will take place on October 19 and has the backing of FACE - the Fight Against Cuts in Education - whose own demonstrations have attracted more than 20,000 parents, governors and children.
The march will start from Victoria Embankment at 1pm and move to Hyde Park where it will be addressed by David Blunkett, Labour's education spokesman, Don Foster, the Liberal Democrat education spokesman, Mr Monks, Mr McAvoy, parents and governors.
The protests come as the funding debate intensifies amid claims by the teacher unions for above inflation pay rises and demands by Government for wage increases to be met from efficiency savings.
In Suffolk, education officials have already been asked to identify cuts of almost Pounds 11 million. Headteachers estimated that this could mean the loss of up to 350 teaching jobs, bigger classes, less money for books and equipment and a reduced teaching day in an attempt to save on the salaries bill.
Parents in Suffolk already pay Pounds 46.50 a term in transport fees for post-16 students. The price of school meals has increased and there are also fees for music, drama and dance lessons.
The county branches of the National Association of Head Teachers and the Secondary Heads Association warned: "Good education in Suffolk is in the firing line. Pupils will suffer and so will their parents. Last year Government took notice of the views of parents, governors and teachers by changing its plans at the last minute.
"Only a similar change in Government funding policy this autumn will save education from significant damage. Otherwise all children in all schools will be affected."