James William Breen (born 1947) is a Research Fellow at Monash University in Australia, where he was a professor in the area of telecommunications before his retirement in 2003. He is well known for his involvement in several popular free Japanese-related projects: the EDICT and JMDict Japanese-English dictionaries, the KANJIDIC kanji dictionary, and the WWWJDIC portal which provides an interface to search them.
His EDICT dictionary and WWWJDIC server have been described as "reliable and close to comprehensive". His 100,000-word lexicon has been used to build other Japanese language learning sites such as Rikai.
He remains a board member of the Japanese Studies Centre at Monash University.