Johan De Farfalla (born June 3, 1971 in Stockholm) is a Swedish bass player. He is the former bassist of seminal Swedish metal band Opeth.
De Farfalla originally joined Opeth in 1991 when its lineup was David Isberg on vocals, Mikael Åkerfeldt and Kim Pettersson on guitar, and Anders Nordin on drums. He replaced Nick Döring on bass for one show and quit immediately afterwards. Opeth recruited Peter Lindgren to replace him for their next show, and then Stefan Guteklint after Lindgren moved to guitar. In 1994, Opeth was approached for signing by Candlelight Records, and fired Guteklint. De Farfalla rejoined Opeth initially as a session bassist for their first album Orchid (1995), but subsequently became an official member again. After touring in support of their second album Morningrise (1996), De Farfalla was fired by Åkerfeldt who cited that De Farfalla was not a good fit. De Farfalla wanted the bass to have a more prominent role in the music of Opeth, something Åkerfeldt felt uncomfortable with.