Staff at Northwood School are facing redundancies because of falling pupil numbers.
The school in Potter Street, Northwood Hills, has seen a huge drop in student intake in the last three years because of other schools in the nearby area receiving outstanding Ofsted reports.
Headteacher Tim Westrip said: "There are some staff redundancies planned, many of which will be met through vacant posts, redeployment, retirement and promotion."
Consultation for the affected posts started on January 12 and finishes today (Wednesday).
Chris Spencer, director of education and children's services at Hillingdon Council, said: "We are working closely with the staff at Northwood School to help find alternative employment in schools across the borough. At this stage we are unaware of the exact number of posts being made redundant."
He pointed to the closeness of Ruislip High and Harefield Academy which have high Ofsted reports and are more popular with parents.
In September 2006 the school had an intake of 80 pupils into Year 7, but last year that fell to just 52. Its results have also fallen, with 33 per cent of pupils achieving five or more A* to C GCSEs in 2007 compared to just 22 per cent last year.