O.
25/01/29 Rear Admiral (Ingenieur) Francis Blake O'Dogherty: CMG.
31/12/35 Captain (Médecine) puis 01/08/44 Rear Admiral (Médecine) Joseph Aloysius O'Flynn.
11/01/38 Rear Admiral Ronald Wolseley Oldham (21/07/1887-): OBE. [Avant la guerre: en retraite.]
09/07/26 Rear Admiral (Retraite) Laurence Richard Oliphant (16/12/1877-06/12/1950): CBE (35). [Avant la guerre: en retraite.]
12/02/32 Rear Admiral Niel O'Neill.
03/05/34 Rear Admiral (Trésorier) (Retraite) George Burton Osborne.