The YouView IPTV service will not launch before the third quarter of 2012, according to the BBC Director General.
A Q1 or Q2 launch for the service - which has encountered numerous technical problems during testing - has previously been mooted.
Speaking to a government Select Committee for the Department of Culture, Media and Sport, Mark Thompson said the much-delayed service is now targeting a July launch.
As reported by ISPreview.co.uk, he noted that the joint venture partners want to make sure the product is entirely stable before it comes to market.
"IPTV turns out to be quite difficult to do," he told MPs.
The YouView partners - which include BT and TalkTalk - recently invited 2,200 members of the public to participate in a full service trial.
When the service launches, consumers will be able to view online and digital content on their televisions using a broadband-connected set-top box.