Guernsey's Blanchelande College has announced it will suspend its sixth form for two years from this summer.
It means pupils currently taking their GCSEs at the school will be forced to find an alternative place to study their A-levels.
Patrick Harland, who will be principal when the current head teacher Lesley Le Page retires, said it was because only 20% of pupils stayed on to do A-levels.
He said the school would review the situation in 2013.
Mr Harland said that review would look at whether or not baccalaureates or vocational courses would be more appropriate to teach.