The company said construction of the The Wizarding World of Harry Potter at the theme park would begin, along with the upgrading of TV production studios and office space on the studio lot. The project would also eventually include a hotel and retail outlets, adding nearly 2 million square feet to the studio complex.
The plan initially called for adding nearly 3,000 residential units, but that was dropped last year after objections from local residents and politicians.
Since the modified plan went through, some nearby residents said it will mean more noise and traffic congestion.
"They're allowed to have explosions at 1 o'clock in the morning and there is no provision or component within the permit that enables this community to get them to stop it," said resident Rick Gombar, whose property overlooks the studio. He said he and others have complained about the noise and county officials are aware of it.
"It's a money grab as far as I'm concerned for the city and the county and they've kind of thrown us under the bus in the process," Gombar said.
The company says the project will mean big money and claims 30,000 jobs will be created during construction and operations.
"It is a place that provides diverse jobs, quality jobs and union jobs," said Corinne Verdery before the Los Angeles County Board of Supervisors.
The company also said there will also be traffic improvements and a bike path along the Los Angeles River.
"This is the first one to really come to the public with a plan to make the Los Angeles River a better place for us all," said Lewis McAdams of Friends of the L.A. River.
The Board of Supervisors tentatively approved the plan, unanimously directing its lawyers to prepare documents for final approval.
Residents said they are ready to head to court to sue Universal in order to stop the project.
The Associated Press contributed to this report.