- BLEDRI ap CYDIFOR (fl. 1116-30), chieftain
- BLEGWRYD - see HUGHES, JOSEPH TUDOR
- BLEGYWRYD (fl. c. 945), an authority on the ancient laws of Wales
- BLETHIN, WILLIAM (fl. 1575 to 1590), bishop of Llandaff
- BLIGH, STANLEY PRICE MORGAN (1870 - 1949), landowner and author
- BLOOM, MILBOURN (d. 1766), Independent minister
- BOB TAI'R FELIN - see ROBERTS, ROBERT
- BODFAN - see ANWYL, JOHN BODVAN
- BODURDA, Bodwrda - see BODWRDA
- BODVEL family Bodvel, Caerfryn,
- BODVEL, CHARLES (1582 - 1647) - see BODVEL
- BODVEL, HUGH (d. 1611), M.P. - see BODFEL
- BODVEL, JOHN (1617 - 1663), Royalist colonel - see BODVEL
- BODWELL, CHARLES (1582 - 1647) - see BODVEL
- BODWRDA family Bodwrda,
- BOHUN, HUMPHREY (c.1250 - 1298) - see CLARE
- BOLD, HUGH (1731 - 1809), lawyer
- BONAPARTE, Prince LOUIS-LUCIEN (1813 - 1891)
- BONARJEE, DOROTHY NOEL (1894 - 1983), poet and lawyer
- BOOTH, FLORENCE ELEANOR (1861 - 1957), Salvationist and social reformer
- BOOTS, JOHN GEORGE (1874 - 1928), Wales and Newport Rugby forward
- BOSANQUET family
- BOSSE-GRIFFITHS, KATE (1910 - 1998), Egyptologist and author
- BOSTON, sixth Baron - see IRBY, GEORGE FLORANCE
- BOWDEN, HERBERT WILLIAM (BARON AYLESTONE), (1905 - 1994), politician
- BOWEN family Llwyn-gwair,
- BOWEN, BEN (1878 - 1903), student and poet
- BOWEN, D.E. (fl. 1840-80), editor, author and Baptist minister in U.S.A.
- BOWEN, DAVID (Myfyr Hefin; 1874 - 1955), minister (B) and editor
- BOWEN, DAVID (1774 - 1853) Felinfoel, minister
- BOWEN, DAVID GLYN (1933 - 2000), minister and multifaith theologian
- BOWEN, EDWARD GEORGE (1911 - 1991), developer of radar and an early radio astronomer
- BOWEN, EMRYS GEORGE (1900 - 1983), geographer
- BOWEN, EVAN RODERIC (1913 - 2001), Liberal politician and lawyer
- BOWEN, HANNAH (1729 - 1805), matron of 'Trevecka Family' - see LLOYD, SIMON
- BOWEN, IVOR (1862 - 1934), K.C., county court judge
- BOWEN, JOHN (1815 - 1859), bishop of Sierra Leone
- BOWEN, SAMUEL (1799 - 1887) Macclesfield, Independent minister and teacher
- BOWEN, SARAH (1727 - 1807), first matron of the Trevecka Family - see LLOYD, SIMON
- BOWEN, THOMAS (1756 - 1827), Independent minister
- BOWND, WILLIAM, Arminian Baptist
- BOWYER, GWILYM (1906 - 1965), minister (Congl.) and college principal
- BOYDELL, JOSIAH (1752 - 1817), painter and illustrator
- BRACE, DAVID ONLLWYN (1848 - 1891), Independent minister
- BRACE, WILLIAM (1865 - 1947), miners' leader and M.P.
- BRADFORD, JOHN (1706 - 1785), weaver, fuller, and dyer
- BRADFORD, SHÔN - see BRADFORD, JOHN
- BRADFORD, SIÔN - see BRADFORD, JOHN
- BRADNEY, Sir JOSEPH ALFRED (Achydd Glan Troddi; 1859 - 1933), historian
- BRANGWYN, Sir FRANK FRANCOIS GUILLAUME (1867 - 1956), painter