Toerger Odegaard, the head of the city's education department, said Oslo's city council wants to ban the burqa and niqab, garments which cover the face.
He said teachers could not do their job properly without seeing their students' faces.
"We will introduce a ban after the summer holidays at the end of August," he told Reuters on Wednesday.
Lawyers at the education ministry had just told the council it would not be illegal under Norwegian law to ban the headdress.
France has banned overt religious symbols at school. In December, the Dutch parliament voted in favour of banning burqas, and the Belgian town of Maaseik has forbidden them through an existing law which required people to be identifiable in public.
Muslims in Norway - which has large Pakistani and Somali minorities concentrated mainly in Oslo - said the move was an encroachment on personal freedom.
Fakhra Salimi, the head of MiRA a partly state-sponsored group that helps female immigrants in Norway, said: "We have been having a discussion about whether you should wear the niqab or not, but making laws which ban it is just going too far."
She said women over the age of 16 should be able to wear the niqab if they chose.