Otto: Name day
Name Day List: Otto
| Country | Day | Month | Names |
 Austria | 23 | March | Otto, Rebecca, Toribio |
 Denmark | 9 | April | Otto, Procopius |
 Sweden | 9 | April | Ottilia, Otto |
 Finland | 17 | April | Otto |
 Estonia | 9 | May | Otto, Ott, Kahru |
| Austria | 30 | May | Ferdinand, Johanna, Otto |
| Austria | 30 | June | Bertram, Ehrentrud, Otto |
 Germany | 30 | June | Otto |
| Austria | 1 | July | Aaron, Dietrich, Otto, Theobald |
 Poland | 2 | July | Juda, Maria, Martynian, Otto, Piotr, Urban |
 USA | 2 | July | Othello, Otis, Otto, Penelope, Penny, Petunia |
| Poland | 3 | July | Anatol, Jacek, Korneli, Leon, Miłosław, Otto |
| Austria | 7 | September | Otto, Ralph, Regina |
| Denmark | 4 | November | Otto |
 Norway | 4 | November | Ottar, Otto |
| Poland | 18 | November | Aniela, Cieszymysł, Filipina, Galezy, Klaudyna, Odo, Otto, Roman, Tomasz |
Name Day List - similar names (Otto)
Croatia 
Hungary 
Italy