Gloucester Academy has secured more than £15m of funding to allow it to move to a single site.
The academy was formed in September 2010 by the merging of Bishop's College and Central Technology College.
The future of the project had been put in doubt following government spending cuts earlier this year.
The funding will help pay for new facilities on the Central Technology College's Cotteswold Road site, where the academy will be based.
Under the previous Labour government the academy had been promised £21m but all school building schemes in the UK were reviewed when the coalition government came into power.
Greg Smith, principal at Gloucestershire College - which is a co-sponsor of the academy - welcomed the news.
"It's great news, obviously it's less than we we're expecting and that's not ideal, but it's better than nothing," he said.
"Now we will go back and look at our plans and go through the procurement process to see how much we need to spend."
Gloucester's Conservative MP Richard Graham said: "This amount is exactly what we were hoping for and is enough with construction costs as they are for a good quality new building.
"This is good news for education and for the construction sector."
Gloucester Academy has 870 pupils aged between 11 and 18 and specialises in digital technology and computing.