Perth and Kinross Council's licensing committee unanimously agreed to allow a variation of organiser DF Concerts' public entertainment licence for the 85,000-capacity music festival.
The company had requested a one-hour extension for Saturday, July 12 to allow the main arena at Balado Airfield near Kinross to stay open later than in previous years.
In recent years the music from the stages has had to stop at midnight although the festival's campsite is allowed to operate until 2am.
Event manager Colin Rodger said: "This change does not alter the overall operational times of the event as a whole with the campsite entertainment times remaining the same by concluding at 2am.
"We have the opportunity to bring two international headliner artists to the T in the Park line-up in a co-headliner format.
"To achieve this both acts would need to perform in darkness which is why we have requested this extension of the operating times.
"In 2013 we were a few thousand short of selling out and bringing these two acts to the line-up we will significantly increase the demand for tickets and hopefully get back to full capacity.
"As a result, the local economic impact will be increased by the several thousand additional customers each day and should see a lift from 2013 which I see as a very tangible benefit to the local communities businesses and residents.
"Following robust discussions and planning with the local community it can be expected that there will be little impact to local residents.
"Our relationship with the local community has grown each year and our constant communication with them has allowed both parties to mutually benefit from the festival in a number of ways."
DF Concerts chief executive Geoff Ellis said: "Headliners want to perform in darkness, and if we were going later on Saturday night, we could close with an electronic headliner."
Residents gave a green light to the licence variation at a meeting last month.