Ivanson Ranny "Johnny" Nelson (born 4 January 1967) is a British retired professional boxer who competed from 1986 to 2005.
He is currently the longest reigning cruiserweight world champion of all time, having held the WBO title from 1999 to 2005, making thirteen successful defences, a record shared with Marco Huck.
Nelson also held the British cruiserweight title twice between 1989 and 1997, and the European cruiserweight title twice between 1990 and 1998.
BoxRec rates him the 2nd greatest cruiserweight of all time.