 Old Orsinium Conqueror | Orsinium / Exploration | 50 |
 Old Orsinium Group Event | Orsinium / Exploration | 50 |
 Old Orsinium Vanquisher | Orsinium / Exploration | 15 |
 Old Sord's Cave Explorer | Exploration / Ebonheart Pact | 10 |
 On a Short Leash | DLC Dungeons / Moon Hunter Keep | 5 |
 On Top | DLC Dungeons / Scalecaller Peak | 50 |
 Once into the Depths | Trials / Dreadsail Reef | 10 |
 Once More, Please | Infinite Archive / General | 10 |
| Ondil Explorer | Exploration / Aldmeri Dominion | 10 |
 One at a Time | Orsinium / Quests | 5 |
 One Core, No More | Trials / Cloudrest | 50 |
 One for Each of You | DLC Dungeons / Bal Sunnar | 10 |
 One Hand and Shield Apprentice | Character / General | 10 |
 One Hand and Shield Master | Character / General | 15 |
 One Last Brawl | Orsinium / Exploration | 10 |
 One-Hundredth Cut | Dark Brotherhood / Exploration | 15 |
| Onkobra Kwama Mine Explorer | Exploration / Ebonheart Pact | 10 |
 Opening Hand | High Isle / Tales of Tribute | 5 |
| Opulent Eradicator | Night Market / Bosses | 50 |
 Orc King's Conqueror | Orsinium / Quests | 10 |
 Orc King's Councilor | Orsinium / Quests | 10 |
 Orc King's Marshal | Orsinium / Quests | 10 |
 Orc Slayer | Player VS Player / General | 10 |
| Orc's Finger Ruins Explorer | Exploration / Daggerfall Covenant | 10 |
 Orcrest Conqueror | Elsweyr / Exploration | 50 |
 Orcrest Group Event | Elsweyr / Exploration | 50 |
 Orcrest Vanquisher | Elsweyr / Exploration | 10 |
 Order of the Hour Style Master | Dark Brotherhood / General | 50 |
 Organized Scholars' Associate | Greymoor / Quests | 10 |
 Organized Scholars' Hireling | Greymoor / Quests | 5 |
 Organized Scholars' Professional | Greymoor / Quests | 15 |
 Ornaug Slayer | Trials / Dreadsail Reef | 10 |
 Orsinium Patron | Orsinium / Exploration | 5 |
| Ossein Cage Conqueror | Trials / Ossein Cage | 10 |
| Ossein Cage Vanquisher | Trials / Ossein Cage | 10 |
| Osteon Daedra Slayer | Trials / Ossein Cage | 10 |
 Out of Formation | DLC Dungeons / Depths of Malatar | 10 |
 Out of Sight | DLC Dungeons / Imperial City Prison | 50 |
 Out of the Frying Pan | DLC Dungeons / White Gold Tower | 15 |
| Outlaw Style Master | Thieves Guild / General | 50 |
 Outstanding Onslaught | Infinite Archive / Exploration | 50 |
 Ozozzachar's Door | Exploration / Dark Anchors | 10 |
 Pack Hunter | DLC Dungeons / Oathsworn Pit | 50 |
 Pact Anchor Shatterer | Exploration / Dark Anchors | 15 |
| Pact Cave Delver | Exploration / Ebonheart Pact | 50 |
 Pact Fisherman | Exploration / Fishing | 10 |
 Pact Skyshard Hunter | Character / Skyshards | 15 |
 Pact with the Inevitable Knower | Infinite Archive / Tales of Tribute | 15 |
 Paragon | Player VS Player / Battlegrounds | 15 |
 Paranoxia Slayer | Trials / Sanity's Edge | 10 |