JFS has announced it is to make teachers redundant because of government cuts.
But Deborah Lipkin, the executive headteacher, stressed the job losses would not affect classroom teaching.
In an email to parents, she said changes to funding from the government and “increased costs across the public sector that we now face, mean that we must take action swiftly to reduce our expenditure.
“Unfortunately, this has led us to the position of having to consider reducing the number of staff, both teaching and non-teaching.”
Announcing a 30-day consultation period, she said there would be “a limited number of job losses".
The “new non-teaching staff structure” would take effect from May 1, with the cut in the number of teachers being implemented from August 31.
“The proposed changes will ensure that we have the levels of teaching staff that will fully meet our needs in all curriculum areas, and will not have an impact on classroom teaching,” she said.
The redundancies at the school, in Kenton, north-west London, come despite a drive to reduce spending in other areas, and an extensive fundraising campaign.
JFS is Europe’s largest Jewish school with over 2,000 pupils.
Earlier this week the Treasury announced a £3.5 billion cut in spending, with Whitehall departments, including the Department of Education, ordered to draw up plans to trim their budgets by up to six per cent.