Gethin Jenkins (born 17 November 1980) is a Welsh former professional rugby union player who played as a prop for Pontypridd, Celtic Warriors, Cardiff Blues and Toulon. At international level, he won 129 caps for Wales. On his 105th appearance in 2014, he became Wales' most-capped player, overtaking the record held by Stephen Jones; having earned his final cap in November 2016, his record was surpassed by Alun Wyn Jones in September 2019. He is one of a small group of Welsh players to have won three Grand Slams.^[1] He also won five caps for the British & Irish Lions on three tours in 2005, 2009 and 2013. He is the sixth most-capped player in rugby union history and the most-capped front-row forward.

He retired from professional rugby union in November 2018 after struggling with a chronic knee injury.^[2] After retirement, he had a number of coaching positions with the Blues and Cardiff RFC. Following some poor performances by Wales in 2020, he joined Wayne Pivac's backroom staff as the national team's defence coach.

Educated at Llwyncrwn Primary School and Bryn Celynnog Comprehensive School in Beddau,^[3] Jenkins first played rugby union aged 13 at Beddau RFC based in Pontypridd.

Jenkins played his youth rugby at Pontypridd and captained his side to a Welsh Cup title in 1998. He became a regular first-team player and was a key figure in highly successful 2000–2003 Pontypridd team that won the final Principality Cup of the pre-regional era and narrowly losing to Sale Sharks in the final of the Parker Pen Shield competition. The 2002 Pontypridd forwards that Jenkins played alongside were the basis of the pack that led Wales to Grand Slam success in 2005, with ex-Pontypridd players making up six of the eight forwards. Following the introduction of Welsh regional rugby, Jenkins joined the Celtic Warriors. When the Warriors folded after just one season, Jenkins signed for the Cardiff Blues.

At the Cardiff Blues he won the Amlin Challenge Cup, and reached the Heineken Cup semi final. After an impressive World Cup 2011, his signature was hotly sought after with Bath, Perpignan and Toulon all chasing a deal for the prop.^[4] Jenkins joined French Top 14 side Toulon for the 2012-13 season.

Jenkins became the ninth Welshman to win a Heineken Cup with Toulon when he played as a replacement in the final against Clermont Auvergne.^[5] Jenkins is only the second Welsh player (along with Rob Howley) to win both European cups, after winning the Amlin Challenge Cup in 2010 with the Cardiff Blues and the Heineken Cup with Toulon in 2013.

Jenkins began his coaching career as defence coach for Cardiff RFC, while still playing for Cardiff Blues.^[15]

In 2020, he assisted with Wales U20, as a defence coach, before joining up with the senior side ahead of the 2020 Autumn Nations Series, as a technical coach.^[16]

Ahead of the 2021 Six Nations, his role was made permanent, becoming the full time defence coach.^[17]

Jenkins usual position is loosehead prop but he has also played in the tighthead prop position. He was one of the "new-breed" of front-rows, known for his speed, fitness and turnover ability, however some criticism was made of his scrummaging at times during his career.

Despite his stern on-field persona, he was a well-respected and well-liked player,^[18] commonly referred to as "Melon".

Jenkins has also played rugby league, making regular appearances for Cardiff Demons in the late 1990s leading them to the 1998 Division Two Academy Grand Final.^[19]