Leó is observed as a name day celebration on April 11th in Hungary.
The masculine name Leó traces its deep history to the Latin word for "lion," establishing its meaning as one associated with royalty and courage. While the accented version is less frequent than the common spelling in the USA, it serves as a sophisticated nod to European tradition and linguistic precision. Historically, this name has been a consistent choice throughout Western civilization due to its simplicity and powerful connotation. Leó projects a strong, regal, and elegant mood, balancing classic tradition with enduring appeal. It is globally recognized exclusively as a boy's name, maintaining a sense of timeless robustness.
| 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 |
 Ukraine | 19 | February | Lev, Leo, Levko |
| 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 |
 Denmark | 11 | April | Leo |
| Lithuania | 11 | April | Daugaile, Leonas, Vykintas |
| Poland | 11 | April | Filip, Herman, Jaromir, Leon, Marek |
 USA | 11 | April | Alger, Algernon, Ari, Ariel, Arielle, Arion, Leo, Leon, Leonel, Leona, Leontine, Lionel |
| Greece | 15 | April | Leonidas, Leo |
| Poland | 15 | April | Anastazja, Bazyli, Leonid, Ludwina, Modest, Olimpia, Tytus, Wacław, Wacława, Wiktoryn, Wszegniew |
| Austria | 19 | April | Gerold, Leo, Marcel |
| 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 |
| Austria | 12 | June | Florinda, Guido, Leo |
| 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 |
| Ukraine | 18 | June | Leon, Leo |
| Czechia | 19 | June | Leoš |
| Austria | 25 | June | Dorothea, Eleonora, Ella |
| France | 25 | June | Aliénor, Eléonore, Prosper, Salomon |
| Denmark | 28 | June | Eleonora |
 Estonia | 28 | June | Leo, Leopold |
 Finland | 28 | June | Leo |
 Norway | 28 | June | Lea, Leo, Leon |
| Poland | 28 | June | Amos, Ireneusz, Józef, Leon, Paweł, Raissa, Zbrosław |
 Sweden | 28 | June | Leo |
| 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 |
| Latvia | 6 | November | Leo, Leonards, Leonhards, Leons, Linards |
| Lithuania | 6 | November | Asmantas, Leonardas, Vygaude |
| Norway | 6 | November | Lennart, Leonard |
| Poland | 6 | November | Feliks, Leonard, Trzebowit, Ziemowit |
| Spain | 6 | November | Leonardo |
| Austria | 10 | November | Andrea, Andreas, Jens, Leo |
| Croatia | 10 | November | Leon Veliki papa, Lavoslav, Lav |
| France | 10 | November | Léon, Noé |
 Germany | 10 | November | Leo |
| 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 |