The government has granted planning permission for the 15-year project including new stages and streetscapes at the site in Iver Heath.
South Bucks District Council (SBDC), which turned down the "inappropriate" plans, said it was "disappointed".
The latest Star Wars film, Episode VII, is currently being filmed at Pinewood.
It has been home to more than 1,500 movies over 76 years including the most recent James Bond movie, Skyfall.
The expansion project, known as the Pinewood Studios Development Framework (PSDF), will double the existing studios by adding a total of 100,000 square metres of new facilities, including 12 large stages, workshops and production offices.
A studio spokesman said the expansion would "secure future growth".
The studio said the decision by the Secretary of State for Communities and Local Government, Eric Pickles, "will address the clear need for additional capacity in the UK".
Pinewood chief executive Ivan Dunleavy said: "We want to begin construction as soon as possible."
In 2012, the government rejected a previous plan, which included more than 1,000 homes.
The studio submitted its latest application in February 2013, following "extensive public consultation".
It was rejected by the local council and the studios submitted its appeal to the Planning Inspectorate the following May.
Nearby councils have always opposed the plans as an expansion into green belt land.
Councillor Roger Reed said SBDC had presented "extensive and well informed objections".
"We must now look forward and recognise the importance of Pinewood and the benefit they can bring to the local and wider economy," he added.
Parish councillor Sylvie Lowe, who represents Iver, said she was "surprised" at the decision and the council was considering its options.
Pinewood Studios is set to double in size after winning an appeal against the rejection of its £200m expansion plan.