Capped by Wales at U20 level, Webb was also a member of the Welsh squad that won the Sevens World Cup in Dubai in 2009. His form this season has seen Webb rewarded with a lengthy run in the team, making 12 appearances so far during the current campaign.
Speaking after signing his contract, Webb said: "I'm very pleased to have re-signed, the Ospreys are moving forward and I'm just happy to be a part of it for another two years. The players and management here have a strong idea of where we want to go, and hopefully we can take the Ospreys onto bigger and better things.
"I had a few injuries last year but I've put them behind me and I'm really enjoying my rugby at the moment. I've had a good run of games that has given me the chance to show what I can do and my confidence is growing. I just want to compete for the number nine jersey.
"There's a lot of competition for places here, but it's an environment that I'm happy in. It's my home region, I'm proud to wear the Ospreys shirt and I'm looking forward to the different challenges of the next two seasons."
Ospreys Head Coach, Sean Holley, added: "This is excellent news, and is further evidence that once again the Ospreys are looking to the future. Rhys has been in our ranks for some time, and much like some of our other youngsters is now starting to mature and blossom. He has become very diligent in his match preparation including getting to know the opposition. Off the back of his hard work he's been given some significant starts this season, and is really competing for the number nine shirt.
"He has the ability to make line-breaks, to quickly learn and adapt in different situations, and he is being rewarded by the selections he's been getting. It's really pleasing that Rhys has been able to develop his game considerably over the course of this season, and he's one who during the World Cup period later this year will be expected to kick-on and deliver some big performances for the Ospreys."