The 41-year-old Take That star is said to have been surprised by the news that the Queen wants to bestow the order of chivalry on him, reported Sun online.
"The Queen was delighted with Gary Barlow's brilliant work and dedication. She made it clear he should be rewarded at the first available opportunity. Mr Barlow was told of Her Majesty's offer a few weeks ago. He was quite surprised, but he has accepted it," a source said.
Barlow had spent over a year organising a star-studded concert at Buckingham Palace as part of the jubilee celebrations, with performers including Stevie Wonder, Paul McCartney, Robbie Williams and Shirley Bassey.
He also toured the commonwealth to record 'Sing', a track he co-wrote with Lord Andrew Lloyd-Webber to mark the occasion.
The singer's OBE is expected to be officially announced next weekend with the release of the queen's birthday honours list.