Eugen has multiple name days celebrated on different dates in various European countries, including Croatia (March 4, May 2, May 21, June 2, December 19), Estonia (June 17), Sweden (November 5), Austria (November 13), and Slovakia (November 18).
Eugen is a masculine name with Greek origins, meaning "well-born" or "noble." It carries an air of classic elegance and quiet strength, often evoking a sense of tradition and refinement. The name has been prevalent across Europe for centuries, maintaining a consistently sophisticated and dignified presence. Its sound is balanced and resonant, contributing to a mood that is both grounded and somewhat distinguished. Eugen is a name that speaks of heritage and inherent grace.
| Country | Day | Month | Names |
 Poland | 4 | January | Angelika, Aniela, Benedykta, Benita, Dobromir, Dobrymir, Eugeniusz, Grzegorz, Izabela, Leonia, Rygobert, Tytus |
 Spain | 4 | January | Eugenio |
 Ukraine | 21 | January | Candid, Candida, Candace, Eugene, Yaroslav, Slavko |
 France | 7 | February | Eugénie |
| Poland | 4 | March | Adrian, Adrianna, Arkadiusz, Arkady, Eugeniusz, Kazimierz, Lew, Łucja, Lucja, Lucjusz, Wacław, Wacława |
| Spain | 4 | March | Francisca, Arcadio, Casimiro, Eugenio |
| Poland | 6 | March | Eugenia, Felicyta, Frydolin, Jordan, Klaudian, Koleta, Róża, Wiktor, Wiktoriusz, Wojsław |
 Lithuania | 2 | June | Aukse, Azuolas, Erazmas, Eugenijus |
| Poland | 2 | June | Efrem, Erazm, Eugeniusz, Marcelin, Maria, Marianna, Mikołaj, Nicefor, Piotr, Racisław |
| Poland | 8 | July | Adrian, Adrianna, Chwalimir, Edgar, Elżbieta, Eugeniusz, Kilian, Prokop, Wirginia |
| France | 13 | July | Enzo, Eugène, Henri, Joël |
| Poland | 13 | July | Ernest, Ernestyn, Eugeniusz, Irwin, Jakub, Justyna, Małgorzata, Radomiła |
| Spain | 13 | July | Eugenio, Sara, Joel |
 USA | 23 | August | Eugene, Eugenia, Geena, Gena, Gene, Genie, Gina, Jina, River, Zaccheus |
| Poland | 6 | September | Albin, Beata, Eugenia, Eugeniusz, Magnus, Michał, Uniewit, Zachariasz |
| Poland | 13 | September | Aleksander, Aureliusz, Eugenia, Filip, Lubor, Materna, Morzysław, Szeliga |
| Lithuania | 15 | September | Eugenija, Nikodemas, Rimgaile, Vismantas |
| Poland | 16 | September | Antym, Cyprian, Edda, Edyta, Eufemia, Eugenia, Franciszek, Jakobina, Kamila, Kornel, Lucja, Łucja, Sebastiana, Sędzisław, Wiktor, Wiktoriusz |
 Slovakia | 18 | September | Eugénia |
| Poland | 13 | November | Arkadiusz, Arkady, Brykcjusz, Eugeniusz, Jan, Mikołaj, Stanisław, Walentyn |
 Estonia | 23 | December | Eugenia, Senna, Senni |
 Greece | 24 | December | Evgenia, Ahmet, Eugenia |
| Ukraine | 24 | December | Eugenia |
 Austria | 25 | December | Anastasia, Eugenia, Josefina, Therese |
 Hungary | 25 | December | Eugénia |
| Lithuania | 25 | December | Eugenija, Gene, Grazvydas, Sanrime |
| Poland | 25 | December | Anastazja, Eugenia, Piotr, Spirydion |
| Spain | 25 | December | Belén, Eugenia, Natividad |
 Italy | 30 | December | Eugenio |
| Poland | 30 | December | Dawid, Dawida, Dionizy, Eugeniusz, Irmina, Katarzyna, Łazarz, Rainer, Sabin, Sewer, Uniedrog |
Croatia 
Sweden