Boyd will now look for a role in coaching.
He was told at the end of last season he would not be offered a new contract, and was linked with several Scottish clubs in a Player/coach role. But he has now decided to quit playing and fully concentrate on coaching.
Boyd, now aged 37, is Celtic's longest serving player, and highlights of his long career include stopping Rangers' 9 in a row, and a testimonial against Manchester United at Parkhead in 2001.
Good luck and Hail Hail to Tom for the future!