Ryan Owen Granville Williams (born 29 October 1969), better known by his stage name Roni Size, is an English DJ and record producer. He came to prominence in 1997 as the founder and frontman of Roni Size & Reprazent, a drum and bass collective. That year they won the Mercury Prize for their debut studio album New Forms.
He resurrected Reprazent in 2008 with the release of a deluxe edition of New Forms on Universal.