A mechanical digger has begun tearing down the old St Peter Port School.
The Les Ozouets campus was built in the 1960s.
Specialist contractors have been removing asbestos, and now a mechanical digger is being used to break the building down.
The site should be levelled by mid-August, to allow a new Guernsey Institute to be constructed.
Institute Head Tracey McClean says the new campus will offer opportunity to many post 16 students:
"In three years time hopefully we will be moving into a brand-new building, so it will mean that we can increase our provision and opportunities on the island.
There's nothing like learning in the classroom and being with a group of peers and sharing ideas."