Union members from 20 schools in Brent are striking this week in the fight for a "fully funded" pay rise.
Teachers from the National Education Union (NEU) will be on picket lines this Wednesday and Friday as part of a national strike campaign across England.
The union claims that since 2010 teachers and staff have a pay rise each September but that it has not been fully funded.
Jenny Cooper, of Brent NEU and the NEU national executive, said schools have to to pay the difference from their own budget, leading to redundancies, particularly of support staff.
She added: "We're seeing more redundancies being made as schools can't afford the staff. We're seeing staff who are unqualified and massive issues of staff shortages.
"That's why we're asking for a fully funded, after-inflation pay rise."
The Government offered teachers a £1,000 one-off payment for the current school year (2022/23) and an average 4.5% rise for staff next year after intensive talks with the education unions.
The Department for Education (DfE) said it was a "fair pay offer to unions which was rejected" and that teachers' pay will now decided by the School Teachers Review Body.
The DfE said school funding in 2024-25 "will be at its highest ever level", in real terms per pupil, as measured by the independent IFS, and funding "is set to rise faster than forecast inflation in both 2023/24 and 2024/25".
Ms Cooper said: "This government does not care about the dire state of our schools - our staffing shortages, our increased class sizes and our lack of money for basic resources.
"They do not care that those who were key workers in the pandemic are now being made redundant and our SEND kids are being left without adequate support. Well we say 'Enough!'- we will not accept this for education- we believe another world is possible."
A Department for Education spokesperson said: “Any strikes action is hugely damaging. We have made a fair and reasonable pay offer to teachers recognising their incredible work and commitment."
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