The pharmaceutical giant's plans for a 1.3m sq ft expansion at its Ulverston site have been given the go ahead by South Lakeland District Council.
The biopharmaceutical manufacturing, office and warehouse facilities will be spread across three buildings.
Start on site is scheduled for the first phase in 2015, which will be developed on a car park on the south of the site. The scheme is expected to take six years to complete.
The healthcare company has occupied the site in Ulverston since 1948.
GSK announced plans to build the factory and hire hundreds of workers at its site in Ulverston in March 2012, it said to increase the production of active ingredients for antibiotics and vaccines. At the time of the announcement, chief executive Sir Andrew Witty said that the factory will be the first GSK manufacturing facility to be built in the UK for nearly 40 years.
GSK employs around 15,000 people in the UK, including 6,000 in manufacturing. GSK's Ulverston site employs around 240 people and manufactures key ingredients for antibiotics.