The first series of Tim Dawson's show scored a 6% share of the 16-34s in the ratings and was in high demand on BBC iPlayer, always ranking in the top ten requested shows on the day after transmission.
"I'm delighted that Coming Of Age has been such a hit with young viewers," said BBC Three controller Danny Cohen.
"The writer Tim Dawson and the young cast are bright emerging stars for the BBC."
BBC head of comedy Mark Freeland commented: "This is a brilliant achievement by an exciting, original writer prepared to take on audience sitcom.
"We are thrilled that BBC Three is backing such young and authentic talent."
Eight new episodes of the coming of age comedy will air in 2009.