- Oakden
- Oakes
- Oakley
- Oakman
- Oates
- Oatley
- Oben
- Ann (between 1831 and 1832 - )
- Oberg
- Oberheim
- Oberlies
- Obey
- Ockenden
- Odd
- Dorcas (between 1827 and 1828 - circa 1902)
- James (before 1808 - )
- Sarah (before 1808 - )
- Sarah (1826 - circa 1894)
- Odeman
- Odemar
- Odman
- Oehlke
- Ogden
- Oglander
- Oke
- Okeover
- Jane (before 1565 - 1620)
- Oldaker
- Oldfield
- Oldroyd
- Olenick
- Oliphant
- Olive
- Oliver
- Oliverson