Rushden Academy parents, staff and students were notified by text and website saying that the school would be closed for a second day.
Principal Jane Burton said: "Due to a gas leak, the school will not be able to open on Tuesday, January 7 as we're unable to provide hot water or heating.
"We're in the process of repairing the issue and aim to be open to staff and pupils on Wednesday, January 8 as usual."
On Friday, a source told the Northants Telegraph that the leak had been discovered as staff opened up the Hayway site in preparation for the new year.
As soon as staff smelt gas they informed gas operator Cadent Gas who isolated the supply.
It is believed the pipe, which is outside and underground, will be located and mended as soon as possible.
A message on the website added: "If the situation changes we will inform you, please check your emails and the school website for any updates."