School leaders will be balloted on strike action in a further escalation of the row over teachers' pay.
The ASCL union, which represents heads and school leaders, said it would formally ballot its members nationally for the first time in its history.
If successful, strike action would be held in the autumn term, the union said.
It comes after 87% of ASCL members voted to reject the government’s pay deal, on a turnout of 56%.
ASCL's General Secretary Geoff Barton said: "ASCL has never before formally balloted at a national level and this is clearly a very significant step.
"The fact that we have reached this point reflects the desperate situation regarding inadequate funding, long-term pay erosion, teacher shortages, and the intransigence of a Government which we can only conclude does not value the education workforce or recognise the severe pressures facing the sector."
He added: "This action is taken as a last resort and with a heavy heart, but we cannot accept the continued damage to education caused by Government neglect and complacency."
ASCL is the last of the major teaching unions to hold a strike ballot over the bitter row on pay.
The National Education Union (NEU) has already held a series of strikes, with further walkouts planned on April 27 and May 2.
The NAHT, which represents heads, and the NASUWT teaching union both failed to meet strict turnout rules in their ballots.
However the NAHT is considering a fresh vote after its members rejected the Government's pay offer.
Downing Street said it did not want to see further disruption to children's education.
The PM's official spokesman said: "I don't want to pre-empt what their members may choose to do.
"We are concerned about the overall impact of strike action on children's education, something that has already been significantly impacted during the global pandemic and we would not want to see that exacerbated by unnecessary strike action."
