Minister Richard Bruton has approved a number of new rooms for Scoil Mhuire National School in Dristeran, Gleneely.
The new build will include a new classroom, user assisted toilets and a Special Education Teacher support.
Approval of the extension has been welcomed by local Councillor Bernard McGuinness.
He welcomes Minister Bruton's announcement and says this is the latest in a series of developments at the school.
Elsewhere in the county, Scoil Adhamhnáin, An Luinnigh, Derrybeg and St Patrick's National School, Murlog, Lifford have been given the green light to carry out emergency mechanical works.
No details have been given on the amount of funding approved by the School Building Unit, detailed letters on the relevant projects will be issued to the school authorities to inform the school authorities of the amount of grant aid sanctioned by the Department.