Building work on St David’s Secondary School in Greystones is due to commence in the coming weeks after a number of previous delays with architectural planning.
The Department of Education had anticipated work would get underway in May of last year, but that failed to materialise.
Planning permission was granted by the County Council in 2016 for refurbishment work of the existing buildings.
The plans also include a new sports centre and fitness suite, technology, art and media rooms and extra parking spaces.
Wicklow TD Stephen Donnelly has welcomed the timing of the announcement, as staff prepare for the arrival of students next week.