The name Gareth means Spear Rule and is of Welsh origin. Gareth is a name that's been used primarily by parents who are considering baby names for boys.
Possibly a form of the name Garrett, or the Welsh word gwaredd meaning "gentle."
Gareth was a Knight of the Round Table in Arthurian legend.
Gareth Keenan is a fictional character in the UK version of the television show, The Office. His US counterpart is Dwight Schrute.