Terence Martin Griffiths (16 October 1947 – 1 December 2024) was a Welsh professional snooker player, coach, and commentator. He won several amateur championships, including the Welsh Amateur Championship in 1975 and consecutive English Amateur Championship titles in 1977 and 1978, before turning professional in 1978 at the age of 30.

Griffiths won the 1979 World Snooker Championship as a qualifier, defeating Alex Higgins in the quarter-finals, Eddie Charlton in the semi-finals, and Dennis Taylor 24–16 in the final. He was only the second qualifier to win the World Championship, after Higgins in 1972; only Shaun Murphy (2005) and Zhao Xintong (2025) have repeated the feat. He reached a second World Championship final in 1988, losing 11–18 to Steve Davis after being level at 8–8.

Between 1984 and 1992, Griffiths reached at least the quarter-finals of the World Championship for nine consecutive years. He won the Masters in 1980 and the UK Championship in 1982, completing snooker’s Triple Crown. He was also runner-up at the Masters three times and reached the final of the 1989 European Open, losing the deciding frame to John Parrott.

Later in his career, Griffiths focused on coaching and mentoring, serving as the World Professional Billiards and Snooker Association's director of coaching. He worked with several leading players, including Stephen Hendry, Mark Williams, and Ding Junhui. Griffiths retired from professional competition in 1997 and died in December 2024, aged 77, following a prolonged illness related to dementia.

Griffiths was born in Llanelli on 16 October 1947. He was admitted to a grammar school but was expelled for truancy and became a student at a secondary modern school, where he played rugby union with future Welsh national-team members Phil Bennett and Derek Quinnell. Griffiths began playing snooker when he was 14. After leaving school at 15, he worked as a blacksmith's apprentice and as a coal miner and became the youngest winner of the Llanelli and District snooker championship at age 16. Griffiths subsequently began working as a bus conductor, a job which gave him more time to practise. He later worked as a postman and as an insurance salesman.

At age 17, Griffiths won the West Wales snooker championship. When he was 18 and working as a bus conductor, he met Annette Jones; they married in 1969. They had their first son, Wayne, a year and a half after their wedding, and their other son, Darren, two years later. Griffiths compiled his first century break at age 24, the first year he entered the Welsh Amateur Championship (where he was runner-up). Griffiths played in the amateur home internationals fourteen times, winning twelve of his matches; after winning the Welsh Amateur Championship in 1975, he reached the quarter-finals of the 1976 World Amateur Snooker Championship. He won the English Amateur Championship in 1977, defeating Sid Hood 13–3 in the final, and retained the title the following year, winning the final 13–6 against Joe Johnson.

Griffiths became a professional player on 1 June 1978 after he was accepted as a member by the World Professional Billiards and Snooker Association (WPBSA) at its meeting during the 1978 World Snooker Championship. Anticipating his acceptance as a professional, Snooker Scene said in May 1978 that "his power screws and long potting are second to no one's ... it will not be in the least surprising, if very soon he becomes a serious challenger for snooker's top professional titles."

In his first professional match, qualifying for the 1978 UK Championship, Griffiths lost 8–9 to Rex Williams after leading 8–2. Williams took a 2–1 lead; Griffiths won the next seven frames, and Williams took the following seven. In the deciding frame, Griffiths rushed when potting the pink ball and went in-off, a foul shot. Williams later potted the pink for the victory. After qualifying for the 1979 World Championship by eliminating Bernard Bennett 9–2 (from 0–2 behind) and Jim Meadowcroft 9–6 (from 6–6), Griffiths defeated the previous year's runner-up Perrie Mans 13–8 in the first round and Alex Higgins 13–12 in the quarter-finals. After beating Eddie Charlton 19–17 in a long semi-final which finished at 1:40 am, Griffiths told interviewer David Vine: "I'm in the final now, you know." In the final, he faced Dennis Taylor, who had been a professional since 1973 and was also playing in his first World Championship final. The match was close for the first four of the six sessions and level at 15–15 before Griffiths took a 17–16 lead and won 24–16, becoming World Champion at his first attempt. It was Griffiths's second tournament as a professional. The result saw him placed eighth in the 1979/1980 world rankings. He was the second player to win the championship after playing in qualifying (after Higgins in 1972), and the first to win it as a qualifier at the Crucible in Sheffield, the venue for the championship since 1977. As of 2025, only two other players have achieved the feat, Shaun Murphy in 2005, and Zhao Xintong in 2025.