One 11-year-old schoolboy has been expelled and another suspended after teachers caught them with cannabis.
Neither of the two boys or their school can be named for legal reasons, but the Gazette understands they were found to have a quantity of the illegal class B drug on them.
One was excluded for five days and the other has been transferred to another school out of the borough.
The head teacher of the school said it has a zero tolerance policy on drugs.
She said: "Sadly, many students are exposed to drugs such as cannabis very widely in social situations and even in the home. It is therefore essential that schools make their positions very clear if they are to be places of safety for young people.
"Like most schools we hope to educate students about the risks of substance abuse in order to pre-empt incidents of this kind. However, ultimately the school has a zero tolerance policy and students and parents know this."
Councillor Ian Gibb, Cabinet Member for Children's Services, said: "There is no place for drugs in schools and we fully support the school's zero tolerance approach."
Within Ealing there is a 'managed move protocol' which enables schools to work together to offer a new start for pupils who meet the criteria for permanent exclusion but who can be quickly integrated into a different school out of the borough.