- ROBERTS, ISAAC (1829 - 1904), astronomer
- ROBERTS, JOHN (Minimus; 1808 - 1880), Calvinistic Methodist minister, and author
- ROBERTS, JOHN (1576 - 1610), Benedictine monk and martyr
- ROBERTS, JOHN (Ieuan Gwyllt; 1822 - 1877), Calvinistic Methodist minister, and musician
- ROBERTS, JOHN (1842 - 1908), Calvinistic Methodist missionary
- ROBERTS, JOHN (1823 - 1893), billiards player
- ROBERTS, JOHN (1767 - 1834), Independent minister and theologian
- ROBERTS, JOHN (J.R.; 1804 - 1884), Independent minister and author
- ROBERTS, JOHN (1775 - 1829), cleric and author
- ROBERTS, JOHN (Alaw Elwy, Telynor Cymru; 1816 - 1894), harpist
- ROBERTS, JOHN (Siôn Robert Lewis; 1731 - 1806), author, almanack-maker, and hymn-writer
- ROBERTS, JOHN (1753 - 1834), Calvinistic Methodist minister
- ROBERTS, JOHN (Siôn Lleyn; 1749 - 1817), poet, schoolmaster, and religious pioneer
- ROBERTS, JOHN (1807 - 1876), musician
- ROBERTS, JOHN (1806 - 1879), musician
- ROBERTS, JOHN (1910 - 1984), preacher, hymnist, poet
- ROBERTS, JOHN (Jack Russia; 1899 - 1979), miner, councillor and a prominent member of the Welsh Communist Party
- ROBERTS, JOHN - see ROBERTS, BARTHOLOMEW
- ROBERTS, JOHN (1879 - 1959), minister (Presb.) and historian
- ROBERTS, JOHN ASKEW (1826 - 1884), antiquary, journalist, and author
- ROBERTS, JOHN BRYN (1843 - 1931), lawyer and politician
- ROBERTS, JOHN FOULKES (1817 - 1902), merchant - see ROBERTS
- ROBERTS, JOHN HENRY (Pencerdd Gwynedd; 1848 - 1924), musician
- ROBERTS, JOHN HERBERT (BARON CLWYD of ABERGELE), (1863 - 1955), politician
- ROBERTS, JOHN IORWERTH (1902 - 1970), schoolmaster and secretary of Llangollen International Eisteddfod
- ROBERTS, JOHN JOHN (Iolo Caernarfon; 1840 - 1914), Calvinistic Methodist minister, poet, and prose-writer
- ROBERTS, JOHN PRICE (1854 - 1905), Wesleyan minister and author
- ROBERTS, KATE (1891 - 1985), author
- ROBERTS, LEWIS (1596 - 1640), merchant and writer on economics
- ROBERTS, LEWIS (Eos Twrog; 1756 - 1844), musician and weaver
- ROBERTS, LEWIS JONES (1866 - 1931), inspector of schools, and musician
- ROBERTS, MARGARET - see HUGHES, MARGARET
- ROBERTS, MICHAEL (1780 - 1849), Calvinistic Methodist minister
- ROBERTS, MICHAEL (d. 1679), principal of Jesus College, Oxford
- ROBERTS, MICHAEL HILARY ADAIR (1927 - 1983), Conservative politician
- ROBERTS, MORRIS (1799 - 1878), Calvinistic Methodist minister, and later Independent minister
- ROBERTS, MORRIS (d. c. 1723), poet, and carpenter
- ROBERTS, MORRIS (fl. c. 1797-1876), miller - see ROBERTS, ELLIS
- ROBERTS, OWEN MADOC (1867 - 1948), minister (Meth.)
- ROBERTS, OWEN OWEN (1793 - 1866), physician and social reformer
- ROBERTS, OWEN OWENS (1847 - 1926), schoolmaster and choral conductor
- ROBERTS, PETER (1760 - 1819), cleric, Biblical scholar and antiquary
- ROBERTS, PETER (fl. 1578-1646), attorney and chronicler
- ROBERTS, RICHARD (Bardd Treflys; 1818 - 1876), poet
- ROBERTS, RICHARD (1823 - 1909), Wesleyan minister
- ROBERTS, RICHARD (1789 - 1864), inventor
- ROBERTS, RICHARD (Gruffydd Rhisiart; 1810 - 1883), writer and Independent preacher
- ROBERTS, RICHARD (1769 - 1855), harpist
- ROBERTS, RICHARD (GWYLFA; 1871 - 1935), Congregational minister, poet and prose-writer
- ROBERTS, RICHARD (1874 - 1945), preacher, theologian and author