Santos que empiezan por 'o'
| Celebration | Name | Saint |
|---|---|---|
| November 18th | Odón | Saint Odo of Cluny |
| March 6th | Olegario | Saint Olegarius |
| June 12th | Onofre | Saint Onophrius of Egypt |
| February 3rd | Oscar | Saint Ansgar of Bremen |
| August 9th | Osvaldo | Saint Oswald of Oswestry |
| July 2nd | Otho | Saint Otho of Bamberg |
| February 15th | Onesimus | Blessed Onesimus |
| December 6th | Obicio | Saint Obicio |
| September 18th | Océano | Saint Océano of Nicomedia |
| November 20th | Octaviano | Saint Octaviano |
| November 20th | Octavio | Saint Octavio of Turín |
| January 1st | Odilón | Saint Odilón of Cluny |
| July 7th | Odón | Saint Odón of Urgel |
| November 3rd | Odrada | Saint Odrada of Alem |
| June 12th | Odulfo | Saint Odulfo of Utrecht |
| March 11th | Oengo | Saint Oengo Cúldeo |
| July 29th | Olav | Saint Olav of Noruega |
| July 11th | Olga | Saint Olga of Kiev |
| July 25th | Olimpíada | Saint Olimpíada of Nicomedia |
| June 12th | Olimpio | Saint Olimpio of Tracia |
| June 3rd | Oliva | Saint Oliva of Anagni |
| July 1st | Oliverio | Saint Oliverio Plunkett |
| February 3rd | Olivia | Saint Olivia mártir |
| September 6th | Onesíforo | Saint Onesíforo of Éfeso |
| August 4th | Onofre | Saint Onofre eremita |
| October 12th | Opilio | Saint Opilio of Piacenza |
| April 22nd | Oportuna | Saint Oportuna |
| July 14th | Optaciano | Saint Optaciano of Brescia |
| June 4th | Optato | Saint Optato of Milevi |
| April 16th | Optato | Saint Optato y compañeros mártires |
| May 1st | Orencio | Saint Orencio |
| December 13th | Orestes | Saint Orestes |
| November 9th | Orestes | Saint Orestes of Capadocia |
| November 10th | Orestes | Saint Orestes of Tiana |
| April 15th | Ortario | Saint Ortario of Landelles |
| March 30th | Osburga | Saint Osburga |
| October 17th | Oseas | Saint Oseas profeta |
| December 4th | Osmundo | Saint Osmundo |
| June 30th | Ostiano | Saint Ostiano of Viviers |
| February 28th | Osvaldo | Saint Osvaldo |
| October 27th | Oterano | Saint Oterano of Iona |
| December 13th | Otilia | Saint Otilia |
| November 16th | Otmaro | Saint Otmaro of Suiza |
| January 16th | Otón | Saint Otón |
| March 23rd | Otón | Saint Otón of Ariano |
| August 6th | Octavian | Blessed Octavian of Savona |
| July 7th | Oddino | Blessed Oddino Barotti |
| December 2nd | Oderisio | Blessed Oderisio |
| January 14th | Odo | Blessed Odo of Novara |
| January 14th | Odoric | Blessed Odoric of Pordenone Mattiuzzi |
| September 10th | Ogier | Blessed Ogier of Locedio |
| November 6th | Olegario | Blessed Olegario Ángel |
| January 28th | Olimpia | Blessed Olympia Bida |
| November 6th | Onofre | Blessed Onofre |
| November 6th | Otilia | Blessed Otilia Alonso González |
| May 30th | Otto | Blessed Otto Neururer |
| October 3rd | Otto | Blessed Otto of Metten |
| September 22nd | Otto | Blessed Otto of Morimond |
| November 6th | Ovidio | Blessed Ovidio Beltrán |