Simon Hughes MP cut the ribbon to mark the official opening of Spa School's new building on Monnow Road.
Spa School is a community special school for pupils with autism.
The new building – which attracted significant opposition from local residents – houses eight new classrooms, including a science lab and a drama space. The funding has also provided a new garden and orchard for the school.
At Monday's ceremony Simon Hughes MP joined more than 100 friends of Spa School in thanking the planners, architects AOC and builders Balfour Beatty for their work.
Mr. Simon Eccles, headteacher of Spa School, said of the building,
"This is a lovely jewel of a building with many beautiful and interesting features, all specifically designed to meet the needs of young people with autism," says headteacher Simon Eccles.
"The result for the school is bigger rooms, smaller class sizes, better facilities and more space."
The celebrations were concluded with music by the popular children's group Kurumi Kidz.