NASUWT members have voted overwhelmingly in favour of strike action over pay and workload.
In States schools, 86% of members who took part in the ballot voted to strike, with 95% voting for industrial action short of strikes.
The turnout was 51% of around 450 members.
Members in seven independent schools also voted in favour of the two options put to them for industrial action.
The union says that the ballot was called because of the States’ ‘failure to address years of real terms pay erosion’.
Teachers in Jersey received, on average, £54,280 in 2022, and new teachers receive around £42,000 on average.
They have rejected a 7.9% pay increase for the 22/23 academic year, arguing it is a 2.5% real terms pay cut compared to inflation.
Other pay States groups, including teaching assistants and caretakers, have accepted the offer, as well as junior doctors, civil servants and manual workers.
Constable Andy Jehan, Vice Chair of the SEB says it has always maintained that its preference is to hold talks and find an agreement.
"All other employees in schools have accepted 7.9 per cent and we maintain it is a fair offer for teachers and a good settlement for the taxpayer."
"We remain open to alternative options presented by the Unions within the affordability limits of public finances."
The NEU has requested a one-year pay deal for 2023 RPI + 5%, whereas NASUWT have called for RPI + 5%, followed by RPI + 4% in 2024 and 2025.
With the suggested pay increases the average salary for a teacher in the island will sit at £61,805.
In comparison with other jurisdictions, Guernsey's teachers recently accepted a 7% pay rise and are on an average of £35,000.
However, teachers in the UK see £28,000 on average and in London, they receive an average of £34,500.
Constable Jehan continues:
"We recognise public servants, including teachers, need to be fairly paid but the public wage bill must be affordable and sustainable."
"We have been clear that the demand for an above-inflation rise is neither realistic nor affordable."
If the suggested pay rise from the unions was accepted, it would mean a £57.9 million increase in expenditure, which the government says puts public finance at risk.
NASUWT's General Secretary Dr Patrick Roach says politicians have been warned that the morale of teachers has been collapsing.
“This situation was completely avoidable, and the fact that members have voted for action is a damning indictment of the States’ complacency and failure to recognise and act to address the escalating crisis within its teaching cohort.
The States now must recognise the depth of anger amongst the profession and seize the limited window of opportunity still available to avoid industrial action.”
A timetable for industrial action will be drawn up in the new academic year if the States don’t recognise the ‘depth of anger’.