- O -
- O'Dell, Etain:
- 1966 BBC Pirates: Mabel (dialogue)
- O'Keefe, Suzanne:
- 1979 D'Oyly Carte Yeomen: Kate
- O'More, Colin:
- 1939 NBC TV Pirates: Samuel
- 1939 NBC TV Pinafore: Captain Corcoran
- O'Neill, Clare:
- 1995 Mackerras/Telarc Yeomen: Kate
- Oakman, John:
- 1993 Karaoke Gilbert and Sullivan: Soloist
- Oakshott, Geoffrey:
- 1963 St. Alban's Rose of Persia: Grand Vizier
- Oberoi, Krishan:
- 1995 Royal Victorian Opera Our Island Home: Mr. Arthur Cecil
- Oke, Alan:
- 1991 New D'Oyly Carte Gondoliers: Giuseppe
- Oldham, Derek:
- 1920 HMV Yeomen: Colonel Fairfax
- 1920 HMV Pirates: Frederic
- 1922 HMV Iolanthe: Earl Tolloller (part)
- 1924 D'Oyly Carte Ruddigore: Richard Dauntless
- 1924 D'Oyly Carte Ida: Hilarion
- 1927 D'Oyly Carte Gondoliers: Marco
- 1926 D'Oyly Carte Mikado: Nanki-Poo
- 1927 D'Oyly Carte Trial: The Defendant
- 1929 D'Oyly Carte Pirates: Frederic
- 1928 D'Oyly Carte Yeomen: Colonel Fairfax
- 1929 D'Oyly Carte Iolanthe: Earl Tolloller
- 1930 D'Oyly Carte Patience: Duke of Dunstable
- 1931 D'Oyly Carte Gondoliers: Marco
- 1931 D'Oyly Carte Pirates: Frederic
- 1931 D'Oyly Carte Ruddigore: Richard Dauntless
- 1931 D'Oyly Carte Yeomen: Colonel Fairfax
- 1932 D'Oyly Carte Ida: Hilarion
- 1933 D'Oyly Carte Sorcerer: Alexis
- 1936 D'Oyly Carte Mikado: Nanki-Poo
- Oldridge, Alfred:
- 1965 D'Oyly Carte Patience Video: Major Murgatroyd
- Olivant, Margaret:
- 1963 St. Alban's Rose of Persia: Moon-upon-the-Waters
- Oliver, Alexander:
- 1982 Brent Walker Sorcerer: Alexis
- 1982 Brent Walker Pirates: Frederic
- 1982 Brent Walker Iolanthe: Strephon
- Oliver, Tim:
- 2001 Ohio Light Opera Utopia, Limited: Capt. Fitzbattleaxe
- Olsen, Dennis:
- 1978 Gilbert and Sullivan Highlights: Soloist
- 1979 More Highlights from Gilbert & Sullivan: Soloist
- 1981 South Australia Pinafore: Sir Joseph Porter
- 1989 Opera Australia Gondoliers: Don Alhambra
- 1995 South Australia Patience: Reginald Bunthorne
- Olsson, Diana:
- 1966 BBC Grand Duke: Lisa (dialogue)
- Ommerlé, Jean:
- 1984 Sweethearts: Soloist
- Orme, Denise:
- 1906 HMV Mikado: Yum-Yum (part)
- Ormiston, Linda:
- 1987 New Sadler's Wells Pinafore: Little Buttercup
- 1987 New Sadler's Wells Ruddigore: Mad Margaret
- Ornadel, Cyril:
- 1962 Martyn Green Sings The Gilbert & Sullivan Songbook: Musical Director
- Orton, Ken:
- 1992 Royal Victorian Opera Mountebanks: Bartolo
- Osborn, Leonard:
- 1949 D'Oyly Carte Pinafore: Ralph Rackstraw
- 1949 D'Oyly Carte Trial: The Defendant
- 1950 D'Oyly Carte Mikado: Nanki-Poo
- 1949 D'Oyly Carte Pirates: Frederic
- 1950 D'Oyly Carte Ruddigore: Richard Dauntless
- 1950 D'Oyly Carte Yeomen: Colonel Fairfax
- 1951 D'Oyly Carte Iolanthe: Earl Tolloller
- 1951 D'Oyly Carte Patience: Duke of Dunstable (part)
- 1955 D'Oyly Carte Princess Ida: Cyril
- Owen, Louise:
- 1991 New D'Oyly Carte Iolanthe: Fleta
- Owen, Meg Wyn:
- 1996 BBC Mikado: Yum-Yum (dialogue)
- 1996 BBC Ruddigore: Rose Maybud (dialogue)
- Oxlade, John:
- 1999 The Masque at Kenilworth: Organist
