Starting with letter O
| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 141 | Osvif | Norse | Father of Gudrun. | M | |
| 142 | Oswald | Shakespearean | 'Tragedy of King Lear' Steward to Goneril. | M | |
| 143 | Oswallt | Welsh | Welsh form of Oswald 'strength from God'. | M | |
| 144 | Osweald | English | Divinely powerful. | M | |
| 145 | Oswin | English | Divine friend; God's friend. | M | |
| 146 | Oszkar | Hungarian | Hungarian form of Oscar 'leaping warrior'. | M | |
| 147 | Otaktay | NativeAmerican | Kills many (Sioux). | M | |
| 148 | Othello | Shakespearean | 'The Tragedy of Othello, Moor of Venice' Othello, the Moor, general of the Venetian forces. | M | |
| 149 | Othmar | Teutonic | Happy fame. | M | |
| 150 | Othni | Biblical | My time, my hour. | M | |
| 151 | Othniel | Biblical | The hour of God | M | |
| 152 | Otis | Greek | Keen of hearing. | M | |
| 153 | Otoahnacto | NativeAmerican | Bull bear (Cheyenne). | M | |
| 154 | Ottah | Egyptian | Third born. | M | |
| 155 | Otto | German | Born eighth or wealthy. | M | |
| 156 | Ottokar | German | Happy fighter. | M | |
| 157 | Ottoway | Teutonic | Lucky in war. | M | |
| 158 | Outram | Teutonic | Wealthy raven. | M | |
| 159 | Ovaegir | Norse | Father of the Skraeling children. | M | |
| 160 | Ove | Swedish | Egg. | M | |