The 21-year-old joins the London side on a one year contract that will see him at the Stoop until the end of the 2011 season.
A key member of the Rhinos academy side, Jones has also enjoyed several representative honours, appearing for Yorkshire and England at under 17’s and under 18’s levels.
Jones cited the success of other youngsters moving to the capital as a key factor in his decision to move to Harlequins:
“Harlequins have a great reputation for developing young players into Super League players; I was in the Leeds Academy with Luke Gale and Ben Kaye who have both had a great first season here, and I hope to follow in their footsteps.
“I’m really excited about moving to London and can’t wait to get started in training with the team and coaches.”
Harlequins head coach, Brian McDermott, said: “Ben has been noted by our coaching staff over the past few years and we look forward to welcoming him to London.”