Gustav: Name day
Name Day List: Gustav
| Country | Day | Month | Names |
 Austria | 10 | March | Emil, John, Gustav |
 Norway | 6 | June | Gustav, Gyda |
 Sweden | 6 | June | Gösta, Gustav |
 Czechia | 2 | August | Gustav |
 Slovakia | 2 | August | Gustav |
 Croatia | 28 | August | Augustin, Tin, Gustav |
 Estonia | 28 | August | August, Gustav, Kustav, Kustas, Kusti, Kusto |
| Sweden | 6 | November | Adolf, Gustav |
Name Day List - similar names (Gustav)
| Country | Day | Month | Names |
 Latvia | 27 | March | Audra, Gustavs, Gusts, Talrits |
 Lithuania | 2 | August | Alfonsas, Guoda, Gustavas, Tautvaldas |
 Spain | 3 | August | Gustavo, Lídia |
| Lithuania | 8 | August | Daina, Domas, Dominykas, Elidijus, Gustavas, Taulgirdas |
 USA | 28 | August | Agustin, August, Augusta, Augustina, Austen, Austin, Austina, Austyn, Gus, Gustava, Gustavo |
 France | 7 | October | Gustave, Serge |