- WILLIAMES, RICE PRYCE BUCKLEY (1802 - 1871), official in the Board of Control, London, and principal founder of The Cambrian Quarterly Magazine
- WILLIAMS family Cochwillan,
- WILLIAMS family Bron Eryri, Castell Deudraeth,
- WILLIAMS family Gwernyfed,
- WILLIAMS family Marl,
- WILLIAMS family Aberpergwm,
- WILLIAMS, ABRAHAM (Bardd Du Eryri; 1755 - 1828), poet and chair manufacturer
- WILLIAMS, ABRAHAM (1720 - 1783), Independent minister
- WILLIAMS, ALBERT CLIFFORD (1905 - 1987), Labour politician
- WILLIAMS, ALICE HELENA ALEXANDRA (ALYS MEIRION; 1863 - 1957), writer, artist, and voluntary welfare worker
- WILLIAMS, Y Fonesig ALICE MATILDA LANGLAND (Alys Mallt, Y Fonesig Mallt Williams; 1867 - 1950), author and celtophile
- WILLIAMS, ALUN OGWEN (1904 - 1970), eisteddfod administrator and supporter
- WILLIAMS, ALYS MALLT - see WILLIAMS, ALICE MATILDA LANGLAND
- WILLIAMS, AMY PARRY - see PARRY-WILLIAMS, AMY
- WILLIAMS, ANEURIN (1859 - 1924), Member of Parliament - see WILLIAMS, EDWARD
- WILLIAMS, ANNA (1706 - 1783), author
- WILLIAMS, ANNE (d. 1770), heiress - see WILLIAMS
- WILLIAMS, ARTHUR WYNN (1819 - 1886), physician and antiquary
- WILLIAMS, BENJAMIN (Gwynionydd; 1821 - 1891), cleric and author
- WILLIAMS, BENJAMIN HAYDN (1902 - 1965), education officer
- WILLIAMS, BENJAMIN MORRIS (1832 - 1903), musician
- WILLIAMS, BENJAMIN THOMAS (1832 - 1890), barrister and educationist
- WILLIAMS, BRANDON MEREDITH RHYS- - see RHYS-WILLIAMS, BRANDON MEREDITH
- WILLIAMS, CATHERINE ANNE - see WILLIAMS, HUGH
- WILLIAMS, CHARLES (1807? - 1877), principal of Jesus College, Oxford
- WILLIAMS, CHARLES (1633 - 1720), benefactor of his native town
- WILLIAMS, Sir CHARLES (d. 1642), politician - see WILLIAMS, Sir TREVOR
- WILLIAMS, Sir CHARLES HANBURY (1708 - 1759), satirical writer and diplomatist
- WILLIAMS, Sir CHARLES JAMES WATKIN (1828 - 1884), Member of Parliament, judge
- WILLIAMS, CHRISTMAS PRICE (1881 - 1965), politician and engineer
- WILLIAMS, CHRISTOPHER DAVID (1873 - 1934), artist
- WILLIAMS, CYRIL GLYNDWR (1921 - 2004), theologian
- WILLIAMS, D. J. - see WILLIAMS, DAVID JOHN
- WILLIAMS, DAFYDD RHYS (Index; 1851 - 1931), author and journalist
- WILLIAMS, DANIEL (1643? - 1716), Presbyterian divine, and benefactor to Nonconformity
- WILLIAMS, DANIEL (1878 - 1968), minister (Meth.) and author
- WILLIAMS, DANIEL HOWELL (1894 - 1963), aerodynamicist
- WILLIAMS, DANIEL JENKINS (1874 - 1952), minister (MC\/Presb.) and official historian of the Welsh Calvinistic Methodist Church of America
- WILLIAMS, DANIEL POWELL (Pastor Dan; 1882 - 1947), founder and first president of the Apostolic Church
- WILLIAMS, DANIEL THOMAS (Tydfylyn; 1820 - 1876), Congregational minister, poet, and musician
- WILLIAMS, DAVID (1877 - 1927), Calvinistic Methodist minister and college tutor
- WILLIAMS, DAVID (1709 - 1784), Independent minister
- WILLIAMS, DAVID (1738 - 1816), littérateur and political pamphleteer
- WILLIAMS, DAVID (1717 - 1792), Methodist exhorter, afterwards Independent minister
- WILLIAMS, DAVID (1779 - 1874), Congregational minister
- WILLIAMS, DAVID (1702 - 1779), early Welsh Moravian
- WILLIAMS, DAVID (Alaw Goch; 1809 - 1863), coal-owner and eisteddfodwr
- WILLIAMS, DAVID (Iwan; 1796 - 1823), Baptist minister
- WILLIAMS, DAVID (1793? - 1845), author
- WILLIAMS, DAVID (1799 - 1869), Member of Parliament - see WILLIAMS