Firefighters are attending a suspected chemical incident on Barretts Grove in Hackney.
A number of people complained of smelling chemicals and fire crews evacuated around 30 people from the school.
Firefighters are carrying out a sweep of the building and found no elevated readings.
The London Ambulance Service assessed a number of people at the scene.
The Brigade was called at 1128 and the incident was over for firefighters by 1258.