Beit Shvidler Primary in Edgware is to launch a 36-hour appeal on Sunday with a £250,000 target.
If the school can raise half the money, donors have pledged to match the rest.
The funds will go towards capital projects as well as meet a shortfall caused by the coronavirus crisis.
As a result of the pandemic, some families have been left unable to pay voluntary contributions towards Jewish studies, while the school has been unable to hire out its hall for functions.