E20 has been greenlit by the BBC, and will focus on four new characters, as yet uncast.
Ten new episodes of EastEnders: E20 will be broadcast on the soap's website in September, before being aired in five televised instalments on BBC Three.
The first series of the youth-oriented drama, which was shown online in January, will also be repeated on BBC Three this month.
The debut series, which followed four teenagers squatting in a flat in Albert Square, drew more than three million views on iPlayer and EastEnders' website.
The new outing will focus on four new, as yet uncast, young characters who live in a flat above Roxy Mitchell's beauty salon.
It will be penned by the team of 13 young writers behind series one, including Emer Kenny, who now stars in the main soap as feisty Zsa Zsa Carter. Her three co-stars from the web spin-off have also made the transition into the terrestrial Walford soap.
Simon Nelson, controller of portfolio and multi-platform at BBC Vision, said: "E20 was one of the most ambitious and successful multi-platform projects we've commissioned.
"We had no hesitation in commissioning another series, something which will delight the 17,000 fans who've been calling for more episodes on the E20 Facebook page."
EastEnders executive producer Bryan Kirkwood added: "Not only have viewing figures been fantastic but - and most importantly - we've had such positive feedback from the viewers."
The first series of EastEnders: E20 will transmit on BBC Three in three 30-minute instalments, starting on Friday April 23 at 8.30pm. Series two will be available at bbc.co.uk/eastenders in 10 14-minute instalments.