The 22-year-old has scored four tries for the Exiles this season including a dramatic last gasp intercept winner to beat Bath at the Kassam Stadium in October in the Aviva Premiership.
Scott huge impact the winger has made at London Welsh since joining on loan in February 2012 from Bath, where he came through the academy.
He played a leading role in the club's Championship success, scoring seven tries in ten appearances during the play-offs.
"I have been at the club just under a year and have thoroughly enjoyed my time here," Scott said.
"I feel my game has improved working with Lyn Jones and the other coaching staff and I'm confident it will continue to do so under their guidance.
"I'm looking forward to the challenge of consolidating London Welsh's Premiership status with a great bunch of teammates."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.