Walter Ogram to Alice Oldfield - 1911 Census household returns
- Walter Ogram to Mary Ohagan
- Patrick Francis Ohagan to Ellen Ohara
- Ellen Ohara to Martin Ohara
- Mary Ohara to Benjamin Ohare
- Bridget Ohare to Theresa Ohea
- Coruching Oheary to Frederick Ohlson
- Frederick Albert Ohlson to John Ohon
- Joseph Ohopkins to Lecoutour Charles Oine
- Alfred Oinn to George Colville Oke
- George Henry Oke to Silas Thomas Jenlyn Oke
- Thomas Oke to John Okeefe
- Leo Okeefe to Margrate Okeilly
- Patrick Okeilly to Harriot Okell
- Harry Okell to Robert Okell
- Salisbury Okell to Heughton Charles Okeover
- Abram Okes to John Frederick Okey
- Joseph Edward Okey to Thomas Joseph Okill
- William Okill to David Aster Okwang
- Frederick Oky to Herbert H Olarenshaw
- Jesse W Olarenshaw to Alfred Francis Old
- Anne Old to Christopher Old
- Clarence Hayden Old to Frank Alfred Charles Old
- Frank John Old to Harry Old
- Harry Old to John Old
- John Old to Mary Ann Old
- Mary Ann Old to Stanley Old
- Stephen Old to William Old
- William Old to Arthur Francis Oldacre
- Aubrey Oldacre to Walter John Oldacre
- William Oldacre to Isaac Oldaker
- James Oldaker to Ernest B Oldale
- Ernest Valentine Oldale to William Oldale
- Alfred Edward Oldall to Ellen Oldbury
- Emily Oldbury to Mary Ann Oldbury
- Mary Jane Oldbury to Joseph Oldcorn
- Joseph Oldcorn to Bessie Olden
- Charles Olden to John Olden
- John Charles Olden to Claus Oldenbuttel
- Henry John Oldenbuttel to George Henry Older
- Harry Older to Alfred Oldershaw
- Alfred Oldershaw to Henry Oldershaw
- Henry Oldershaw to Samuel Oldershaw
- Samuel Oldershaw to William Joseph Isaac Oldershaw
- William Watson Oldershaw to Albert Oldfield
- Albert Oldfield to Alice Oldfield