Rhys Haydn Williams (14 July 1930 – 27 January 1993), born in Cwmllynfell, was a Welsh rugby union lock forward who gained 23 caps for Wales and ten consecutive caps for the British Lions.
At club level he played primarily for Llanelli RFC, captaining them for a season.
He also represented the Barbarians becoming the most capped Welsh representative of the club.
In his later life he became a sports administrator, including the role of vice-president of the Welsh Rugby Union.
Rugby historian John Griffiths described Williams as "the finest line-jumper in the world" and "the most accomplished British lock of the 1950s".