- PHILLIPS, JOHN (Tegidon; 1810 - 1877), printer and poet
- PHILLIPS, JOHN ROLAND (1844 - 1887), historian
- PHILLIPS, MORGAN (d. 1570), Roman Catholic priest
- PHILLIPS, MORGAN HECTOR (1885 - 1953), headmaster
- PHILLIPS, MORGAN WALTER (1902 - 1963), general secretary of the Labour Party
- PHILLIPS, PEREGRINE (1623 - 1691), Puritan preacher; Independent 'apostle of Pembrokeshire'
- PHILLIPS, PHILIP ESMONDE (1888 - 1960), Rear Admiral
- PHILLIPS, REGINALD WILLIAM (1854 - 1926), botanist
- PHILLIPS, SAMUEL LEVI (c. 1730 - 1812), banker and jeweller
- PHILLIPS, Sir THOMAS (1801 - 1867), barrister and author
- PHILLIPS, THOMAS (1772 - 1842), Congregational minister, and master of Neuadd-lwyd school, Cardiganshire
- PHILLIPS, THOMAS (1806 - 1870), Calvinistic Methodist minister, and Welsh secretary of the British and Foreign Bible Society
- PHILLIPS, THOMAS (1868 - 1936), Baptist minister
- PHILLIPS, THOMAS (1760 - 1851), surgeon and benefactor of education
- PHILLIPS, THOMAS BEVAN (1898 - 1991), minister, missionary and college principal
- PHILLIPS, THOMAS LLOYD (1832 - 1900), minister - see PHILLIPS, THOMAS
- PHILLIPS, Sir THOMAS WILLIAMS (1883 - 1966), permanent secretary to the Ministry of Labour and National Service
- PHILLIPS, WILLIAM (1822 - 1905), botanist and antiquary
- PHILOMATH - see DAVIES, EVAN
- PHILOMATH - see PRYS, JOHN
- PHILOTHEOROS - see OWEN, WILLIAM
- PHYLIP family, poets Ardudwy
- PHYLIP BRYDYDD (fl. 1222), court poet
- PHYLIP, GRUFFYDD (d. 1666), poet - see PHYLIP
- PHYLIP, PHYLIP JOHN (d. 1677), poet - see PHYLIP
- PHYLIP, PHYLIP SION (d. 1677), poet - see PHYLIP
- PHYLIP, RHISIART (d. 1641), poet - see PHYLIP
- PHYLIP, ROBERT (1609 - 1679), author - see PUW
- PHYLIP, SIÔN (1543? - 1620), poet - see PHYLIP
- PHYLIP, WILLIAM (1579/80? - 1669/70), poet - see PHYLIP
- PICTON, CESAR (c. 1755 - 1836), coal merchant
- PICTON, Sir THOMAS (1758 - 1815), soldier, colonial governor and enslaver
- PICTON, Sir THOMAS (1758 - 1815), a soldier
- PICTON-TURBERVILL, EDITH (1872 - 1960), worker for women's causes and author
- PIERCE, ELLIS (Elis o'r Nant; 1841 - 1912), author of historical romances and bookseller
- PIERCE, JOHN (1889 - 1955), author, minister (Presb.) and schoolteacher
- PIERCE, THOMAS JONES (1905 - 1964), historian
- PIERCE, THOMAS MORDAF (1867? - 1919), Calvinistic Methodist minister, and author
- PIERCE, WILLIAM (1853 - 1928), Congregational minister and historian
- PIERCY, BENJAMIN (1827 - 1888), civil engineer
- PIERCY, ROBERT (1825 - 1894), civil engineer
- PIOZZI, HESTER LYNCH (1741 - 1821), author
- PODE, Sir EDWARD JULIAN (1902 - 1968), accountant and industrialist
- POET JONES - see JONES, JOHN
- PONSONBY, SARAH (1755 - 1831), one of the 'Ladies of Llangollen'
- PONTYPRIDD, Baron - see THOMAS, ALFRED
- POOLE, EDWIN (1851 - 1895), journalist, printer, and local historian
- POPKIN, JOHN (fl. 1759-1824), Methodist and Sandemanian exhorter
- POWEL, ANTHONY (c. 1560 - 1618/19), gentleman and genealogist
- POWEL, CHARLES (1712 - 1796), antiquarian