The all girls school in Holt Lane, Wokingham, welcomed John Redwood, MP, and town Mayor Cllr Martin Bishop to unveil their new humanities block.
The 10 classroom block with house history, geography and the philosophy of religion.
Taking just three months to complete - as it was built off site then transported to the school - the new building features a perspex plaque acknowledging all those who donated towards it.
Costing around £1.5 million, the majority of the funding - £900,000 - came from a government grant the school applied for.
The Holt Association and the parents association fundraised the remainder, with initiatives such as the 'buy a brick’ campaign, which saw people 'buy’ a brick for £25.
Tim Griffith, assistant headteacher, said: “We wanted to have a member of the government there to recognise the funding we received. We got the funding last April, but have been getting planning permission and designing the building since then.
“There’s been a very positive response. The girls have been coming in and out taking a look around, they especially like the pink toilets.”
Mr Griffith added they would now be refurbishing the classrooms the humanities department previously occupied, but had no more big plans.
He added: “We’re a small site, although we do have two temporary classrooms we’re looking to upgrade.”