| Oakeshott of Seagrove Bay (Barony) |
Matthew Alan Oakeshott - Mon 1st May 2000
|
- |
- |
| Oakley (Barony) |
George Cadogan - Sat 10th Sep 1831
|
- |
- |
| Oaksey (Barony) |
Geoffrey Lawrence - Mon 13th Jan 1947
|
- |
- |
| Oakshott (Barony) |
Hendrie Dudley Oakshott - Fri 21st Aug 1964
|
1 February 1975 |
- |
| Oates (Barony) |
Jonathan Oates - Mon 5th Oct 2015
|
- |
- |
| O'Brien (Barony) |
Peter O'Brien - Sat 16th Jun 1900
|
7 September 1914 |
- |
| O'Brien (Barony) |
Murrough O'Brien - Wed 21st Oct 1654
|
- |
- |
| O'Brien of Lothbury (Barony) |
Leslie Kenneth O'Brien - Wed 14th Mar 1973
|
24 November 1995 |
- |
| O'Cathain (Barony) |
Detta O'Cathain - Fri 21st Jun 1991
|
23 April 2021 |
- |
| Ockham (Viscountcy) |
William King - Sat 30th Jun 1838
|
31 January 2018 |
- |
| Ockingham (Barony) |
George - Wed 6th Apr 1689
|
- |
- |
| O'Donnell (Barony) |
Augustine Thomas O'Donnell - Tue 10th Jan 2012
|
- |
- |
| of Offaly (Earldom) |
James Fitzgerald - Thu 19th Mar 1761
|
- |
- |
| Offord of Garvel (Barony) |
Malcolm Ian Offord - Wed 13th Oct 2021
|
- |
- |
| Ogilvy of Airlie (Lordship) |
James Ogilvy - Thu 28th Apr 1491
|
- |
- |
| Ogilvy of Cullen (Lordship) |
James Ogilvy - Tue 24th Jun 1698
|
- |
- |
| Ogilvy of Deskford and Cullen (Lordship) |
James Ogilvy - Fri 24th Jun 1701
|
- |
- |
| of Ogle (Earldom) |
William Cavendish - Mon 16th Mar 1665
|
26 July 1691 |
- |
| Ogle (Viscountcy) |
William Ogle - Sat 23rd Dec 1645
|
- |
- |
| Ogmore (Barony) |
David Rees Rees-Williams - Mon 10th Jul 1950
|
- |
- |