Janith is both a given name and a surname.
Notable people with the given name include: Janith Liyanage (born 1995), Sri Lankan cricketer Janith Silva (born 1990), Sri Lankan cricketer
Janith Koralla (born 2011), Child prodigy, Chess player
Janith Pathirage (born 1990), Sri Lankan book reviewer
Notable people with the surname include: Buddika Janith (born 1989) is a Sri Lankan cricketer