The Texan native passed away after a short illness, his publicist said.
Williams began his solo career in 1971, amassing 17 number one country hits.
His songs, such as Gypsy Woman and Tulsa Time, were covered by many other singers – including Eric Clapton and Pete Townshend. Williams was known as the gentle giant of country music.
Other hits included You’re My Best Friend, I Believe in You and Lord, I Hope This Day Is Good.