Muttiah Muralitharan (born April 17, 1972) is a Sri Lankan cricketer (off spinner) and member of the Sri Lankan national cricket team since 1992. He is the most statistically effective off spin bowler ever to play test cricket. In 2002, Wisden named him as the greatest spinner of all time.

He was born in Kandy, the eldest of four sons to father Muttiah Sinnasmy. At the age of nine he went to St Anthony's College.

He made his test debut against Australia at Colombo in the Australian cricket tour of Sri Lanka, 1992 and ODI debut against India also at Colombo (at the same ground) in 1993.

Muralitharan's bowling action is highly controversial amongst many observers of cricket, as to some it appears that it contravenes the laws of the game by straightening the arm in the course of the delivery. The controversy came to a head after Australian umpire Darrell Hair called a "no ball" for an illegal action seven times during the Boxing Day Test match in Melbourne, Australia, in 1995. After discussions between the Australian Cricket Board and the Board of Control for Cricket in Sri Lanka, Hair umpired no further games involving Sri Lanka in the season.

See: cricket for laws of the game

Muralitharan was later no-balled for throwing by Australian umpires Ross Emerson and Tony McQuillan in an ODI (one-day international) against England, in Brisbane, Australia, later in the same summer. Following this season, Muralitharan underwent biomechanical tests in Hong Kong and Australia under the supervision of bowling experts, who cleared his action as legal, citing a congenital defect in Muralitharan's arm which makes him incapable of straightening it, but giving the appearance of the arm straightening in the bowling action.

Doubts about Muralitharan's action persist, particularly in Australia and England. In 1999, he was once again called for throwing by umpire Ross Emerson in an ODI against England, at the Adelaide Oval in Australia. The Sri Lankan team almost abandoned the match, but after instructions from the president of the BCCSL (relayed to captain Arjuna Ranatunga by mobile phone) the game resumed.