Leo's name day is observed on February 19th and June 18th in Ukraine. The date April 11th is recognized for the name day in Denmark, Hungary, and the USA, while Greece observes it on April 15th. Furthermore, June 28th marks the name day in Estonia, Finland, Norway, and Sweden. Austria celebrates on multiple dates: April 19th, June 12th, and November 10th, with Germany also using November 10th and Latvia recognizing November 6th.
The classic name Leo is a globally recognized masculine choice stemming from the Latin word for "lion," meaning strength and courage. Historically prominent in Europe, the name has seen a major revival in the USA, establishing itself firmly among top contemporary baby names. Leo projects a strong, powerful, and elegantly simple mood, suggesting a confident and commanding personality. Its long history ensures it remains a timeless option, bridging ancient usage with modern appeal. This identity is universally categorized as a male given name across most regions. The name’s brevity contributes to its powerful, assertive tone.
| Country | Day | Month | Names |
 Hungary | 4 | January | Titusz, Leona, Angel |
 Poland | 4 | January | Angelika, Aniela, Benedykta, Benita, Dobromir, Dobrymir, Eugeniusz, Grzegorz, Izabela, Leonia, Rygobert, Tytus |
 Austria | 10 | January | Leonie, Paulus, Wilhelm |
| Poland | 13 | January | Bogumił, Bogusąd, Bogusława, Godfryd, Gotfryd, Leoncjusz, Melania, Weronika |
 Italy | 14 | January | Leonzio, Llario di Poitiers |
 Lithuania | 17 | January | Beatrice, Dovainis, Leonile, Vilda |
| Lithuania | 28 | January | Gedautas, Leonidas, Nijole |
| Poland | 28 | January | Agnieszka, Augustyn, Flawian, Ildefons, Julian, Karol, Leonidas, Piotr, Radomir, Roger, Waleriusz |
 Greece | 18 | February | Leon, Agapitos |
| Poland | 19 | February | Arnold, Arnolf, Bądzisława, Gabin, Henryk, Konrad, Konrada, Leoncjusz, Manswet, Marceli |
| Lithuania | 20 | February | Eitvyde, Leonas, Visgintas |
| Poland | 20 | February | Euchariusz, Eustachiusz, Eustachy, Leon, Ludmiła, Ludomiła, Ostap, Siestrzewit |
 Croatia | 21 | February | Petar, Damir, Eleonora |
| Hungary | 21 | February | Eleonóra |
 Latvia | 21 | February | Eleonora |
| Lithuania | 21 | February | Eleonora, Feliksas, Kestutis, Zemyna |
| Poland | 21 | February | Eleonora, Feliks, Fortunat, Kiejstut, Teodor, Wyszeniega |
 Slovakia | 21 | February | Eleonóra |
 Spain | 22 | February | Margarita, Leonor |
| Poland | 27 | February | Aleksander, Anastazja, Auksencjusz, Gabriel, Gabriela, Honoryna, Leander, Leonard, Sierosława |
| Austria | 1 | March | Albin, Leontina, Roger |
| Greece | 3 | March | Kleonikos |
| Italy | 3 | March | Basileo |
| Hungary | 6 | March | Leonóra, Inez |
| Poland | 14 | March | Bożeciecha, Jakub, Leon, Matylda, Mechtylda, Michał |
 Czechia | 22 | March | Leona |
| Croatia | 9 | April | Marija Kleofina, Demetrije |
| Italy | 9 | April | Maria di Cleofa |
| Lithuania | 9 | April | Aurimas, Dalia, Kleopas, Rasa |
| Hungary | 11 | April | Leó, Szaniszló |
| Lithuania | 11 | April | Daugaile, Leonas, Vykintas |
| Poland | 11 | April | Filip, Herman, Jaromir, Leon, Marek |
| Poland | 15 | April | Anastazja, Bazyli, Leonid, Ludwina, Modest, Olimpia, Tytus, Wacław, Wacława, Wiktoryn, Wszegniew |
| Lithuania | 19 | April | Aiste, Eirimas, Leonas, Leontina, Simonas |
| Poland | 19 | April | Adolf, Adolfa, Adolfina, Alf, Cieszyrad, Czech, Czechasz, Czechoń, Czesław, Leon, Leontyna, Pafnucy, Tymon, Werner, Włodzimierz |
| Spain | 19 | April | León, Crescencio |
| Austria | 22 | April | Alfred, Kaj, Leonidas |
| Lithuania | 22 | April | Leonas, Leonidas, Norvaide, Visgailas |
| Poland | 22 | April | Heliodor, Kajus, Leonia, Leonid, Łukasz, Soter, Strzeżymir, Teodor |
 USA | 22 | April | Caia, Caissa, Kai, Kaila, Kailey, Kaleigh, Kaley, Kay, Kayla, Kaylee, Kayleigh, Kayley, Kaylie, Kaylin, Kaylyn, Leonidas, Makayla, Mckayla |
| Spain | 24 | April | Leoncio, Honorio, Honoria, Fidel |
| Croatia | 12 | May | Leopold Mandic |
| Spain | 12 | May | Domingo, Nerea, Nereo, Aquileo, Flavia, Domitila |
| Latvia | 23 | May | Leontine, Ligija, Lonija |
| Poland | 23 | May | Budziwoj, Dezyderiusz, Dezydery, Emilia, Iwona, Jan, Leontyna, Michał, Symeon |
| Lithuania | 27 | May | Augustinas, Brunonas, Leonora, Virgaudas, Zymante |
| Poland | 12 | June | Antonina, Bazyli, Jan, Leon, Onufry, Wyszemir |
| Poland | 15 | June | Abraham, Angelina, Bernard, Jolanta, Leona, Leonida, Nikifor, Wit, Witold, Witołd, Witolda, Witosław, Wodzisław |
 Denmark | 18 | June | Leontius |
 France | 18 | June | Léonce |
| Poland | 18 | June | Efrem, Elżbieta, Gerwazy, Leonia, Marek, Marina, Paula |
| Czechia | 19 | June | Leoš |
| Austria | 25 | June | Dorothea, Eleonora, Ella |
| France | 25 | June | Aliénor, Eléonore, Prosper, Salomon |
| Denmark | 28 | June | Eleonora |
| Poland | 28 | June | Amos, Ireneusz, Józef, Leon, Paweł, Raissa, Zbrosław |
| Spain | 30 | June | Marcial, Leonila |
| Poland | 3 | July | Anatol, Jacek, Korneli, Leon, Miłosław, Otto |
 Estonia | 8 | July | Ellinor, Eleonoora, Leonoora, Loora, Loore, Noora, Nora |
| Lithuania | 9 | July | Algirdas, Algirde, Leonardas, Veronika |
 Finland | 11 | July | Elli, Noora, Nelli, Eleonoora, Elea |
| Latvia | 11 | July | Leonora, Lore, Svens, Varaidotis |
 Sweden | 11 | July | Eleonora, Ellinor |
| Poland | 17 | July | Aleksander, Aleksy, Andrzej, Bogdan, Dzierżykraj, Januaria, Julietta, Leon, Marceli, Marcelina, Maria Magdalena |
| Poland | 20 | July | Czech, Czechasz, Czechoń, Czesław, Eliasz, Heliasz, Hieronim, Leon, Małgorzata, Paweł, Sewera |
| Austria | 27 | July | Berthold, Natalie, Pantaleon |
| Poland | 27 | July | Alfons, Alfonsyna, Aureli, Julia, Laurenty, Lilla, Marta, Natalia, Natalis, Pantaleon, Rudolf, Rudolfa, Rudolfina, Wszebor |
| Poland | 28 | July | Innocenta, Innocenty, Marcela, Pantaleon, Samson, Świętomir, Wiktor, Wiktoriusz |
 Ukraine | 8 | August | Amelia, Amilian, Emil, Emily, Fedir, Theodore, Leonid |
| Poland | 12 | August | Bądzisław, Hilaria, Klara, Lech, Leonida, Piotr |
| Lithuania | 15 | August | Napalys, Napoleonas, Sigita, Visvilas, Vydene |
| Poland | 15 | August | Maria, Napoleon, Stefan, Stella, Trzebimir |
| USA | 15 | August | Madonna, Malia, Mara, Maria, Mariah, Marian, Mariana, Maribel, Marie, Marisa, Marissa, Maritza, Marla, Mary, Maryann, Mimi, Miriam, Mitzy, Molly, Napoleon, Polly |
| Slovakia | 16 | August | Leonard |
| USA | 18 | August | Aileen, Eileen, Elaina, Elaine, Eleanor, Elena, Eliana, Ella, Elle, Ellen, Ellie, Helen, Helena, Iliana, Lena, Leonora, Nell, Nellie, Nelly |
| USA | 25 | August | Dorcas, Lanard, Lennie, Lenny, Leonard, Leonardo, Tabatha, Tabitha |
| Croatia | 25 | September | Nikola of Flue, Aurelija, Kleofa, Firmin |
| Denmark | 25 | September | Cleophas |
| Lithuania | 25 | September | Aurelija, Kleopas, Ramvyde, Vaigintas |
| Poland | 25 | September | Aureli, Aurelia, Aurelian, Franciszek, Gaspar, Herkulan, Kamil, Kleofas, Kleopatra, Ładysław, Piotr, Rufus, Świętopełk, Wincenty, Władysław, Władysława, Włodzisław |
| Estonia | 28 | September | Leonhard, Lennart, Linnart, Linnar, Lenno |
| Finland | 28 | September | Arja, Lenni, Leon |
| Sweden | 28 | September | Lennart, Leonard |
| Poland | 30 | September | Grzegorz, Hieronim, Honoriusz, Imisław, Leopard, Sofia, Wera, Wiera, Wiktor, Wiktoriusz, Zofia |
| Poland | 2 | October | Dionizy, Leodegar, Stanimir, Teofil, Trofim |
| Croatia | 9 | October | Ljudevit Bertran, Dionizije, Ivan Leon |
| Lithuania | 15 | October | Domante, Gailiminas, Leonardas, Terese |
| France | 19 | October | Cléo, René |
| Greece | 19 | October | Kleopatra, Cleo |
| Lithuania | 19 | October | Geisvilas, Kantrime, Kleopatra, Laura |
| USA | 19 | October | Cleo, Cleon, Cleopatra, Howard, Howie |
| Latvia | 20 | October | Leonids, Leonija |
| Poland | 20 | October | Budzisława, Irena, Jan Kanty, Kleopatra, Wendelin, Witalis |
| Ukraine | 1 | November | Kuzma, Leonard |
| Austria | 6 | November | Christine, Leonhard, Rudolf |
| Croatia | 6 | November | Leonard pust., Vedran, Sever |
| Denmark | 6 | November | Leonhardus |
| France | 6 | November | Bertille, Léonard |
| Greece | 6 | November | Leonardo |
| Italy | 6 | November | Leonardo di Noblac |
| Lithuania | 6 | November | Asmantas, Leonardas, Vygaude |
 Norway | 6 | November | Lennart, Leonard |
| Poland | 6 | November | Feliks, Leonard, Trzebowit, Ziemowit |
| Spain | 6 | November | Leonardo |
| Croatia | 10 | November | Leon Veliki papa, Lavoslav, Lav |
| France | 10 | November | Léon, Noé |
| Italy | 10 | November | Leone I Magno |
| Lithuania | 10 | November | Andrius, Galvyde, Leonas, Vaisviltas |
| Poland | 10 | November | Andrzej, Lena, Leon, Ludomir, Nelly, Nimfa, Probus, Stefan |
| Spain | 10 | November | Almudena, León |
| Austria | 15 | November | Albert, Leopold, Leopoldine |
| Croatia | 15 | November | Albert Veliki, Leopold |
| Czechia | 15 | November | Leopold |
| Denmark | 15 | November | Leopold |
| France | 15 | November | Albert, Arthur, Léopold, Malo, Victoire |
| Latvia | 15 | November | Leopolds, Lipsts, Unda, Undine |
| Lithuania | 15 | November | Albertas, Leopoldas, Vaidilas, Zadvyde |
| Poland | 15 | November | Albert, Alberta, Albertyna, Artur, Artus, Idalia, Leopold, Leopoldyna, Przybygniew, Roger |
| Slovakia | 15 | November | Leopold |
| Spain | 15 | November | Alberto, Leopoldo |
| Sweden | 15 | November | Leopold |
| USA | 15 | November | Leopold, Leopolda, Leopoldo, Leopoltine, Talia, Thalia |
| Poland | 16 | November | Aureliusz, Dionizy, Edmund, Gertruda, Leon, Marek, Maria, Niedamir, Otomar, Paweł, Piotr |
| Croatia | 26 | November | Konrad, Leonardo, Dubravko |
| Poland | 26 | November | Delfin, Dobiemiest, Jan, Konrad, Konrada, Lechosław, Lechosława, Leonard, Sylwester |
| Poland | 27 | November | Damazy, Dominik, Leonard, Maksymilian, Oda, Stojgniew, Walery, Wirgiliusz |
| Lithuania | 9 | December | Gedene, Leokadija, Vakaris, Valerija |
| Poland | 9 | December | Delfina, Joachim, Joachima, Leokadia, Loda, Waleria, Wielisława, Wiesław |
| Greece | 21 | December | Themistokleous, Ioulia, Julia, Julie |
Germany