The origin of the surname Williams can be:
- Son or descendant of Guillemin, a pet form of Guillaume, the French form of William.
- From the Belgic "guild-helm," harnessed with a gilded helmet or "welhelm," the shield or defense of many.
- Derived from the given name "William," an Old French given name with Germanic elements: wil = desire, will; and helm = helmet, protection.
In Wales, adding an "s" to the end of a surname denotes "son of," pointing to Wales as the origin of many people with the Williams surname.
Variations: Willimon, William, Williman, Williamson, Wilcox, MacWilliams, McWilliams, Willihelm, Willelm