The primary school is in the village of Rhoose, approximately five miles outside Barry in the Vale of Glamorgan.
The school also has a nursery unit.
Police have said a car overturned outside the school and that casualties have been taken to hospital.
More top news
Crystal Palace midfielder Joe Ledley has made Chris Coleman's 23-man squad which will travel to France for Euro 2016.
Roy Hodgson has whittled down his provisional squad to confirm the final 23 players who will represent England at Euro 2016.
West is best for warm sunshine as east gets hit by cloud and rain.