Organisers want to raise capacity to 85,000 from 2011
Reading Festival has been allowed to increase its capacity by 6,500 over the next two years.
Councillors backed organisers' plans to boost this year's capacity of 78,500 ticketholders and 4,999 guests to 82,000 next year and 85,000 from 2011.
Resident groups had raised concerns over an increase in noise and a condition to ensure levels are "adequate" has been included.
This year's event, from 28-30 August, will feature Arctic Monkeys.
Organiser Melvin Benn also won agreement for the number of "early arrivals" permitted to be increased from 7,500 to 20,000.
These allow festival-goers to enter the site at 1800 BST on the Wednesday instead of Thursday.