The name day for Aleks is recognized in Estonia, where the celebration occurs annually on September 11.
Aleks is a popular masculine given name used independently around the world, though it often functions as a dynamic short form of Alexander. This strong name carries the ancient Greek meaning of "defender of mankind," emphasizing protection and leadership. Historically prominent in Eastern European cultures, its concise spelling appeals greatly to modern sensibilities. The name projects a mood that is robust, agile, and confidently efficient, avoiding unnecessary formality. Globally, Aleks is consistently classified as a male identifier, reflecting its widely understood historical usage.
| Country | Day | Month | Names |
 Poland | 15 | January | Aleksander, Dąbrówka, Dobrawa, Domasław, Domosław, Izydor, Makary, Maur, Paweł |
| Poland | 12 | February | Aleksy, Benedykt, Eulalia, Julian, Laurenty, Modest, Nora, Radzim, Trzebisława |
 Norway | 17 | February | Aleksandra, Sandra, Sondre |
 Croatia | 25 | February | Aleksandar, Alka, Sandra, Branimir |
 Lithuania | 26 | February | Aleksandras, Aurime, Izabele, Jogintas |
| Poland | 26 | February | Aleksander, Bogumił, Cezariusz, Dionizy, Mirosław, Nestor |
| Poland | 27 | February | Aleksander, Anastazja, Auksencjusz, Gabriel, Gabriela, Honoryna, Leander, Leonard, Sierosława |
| Poland | 10 | March | Aleksander, Bożysław, Cyprian, Makary, Marceli, Porfirion |
| Norway | 18 | March | Aleksander, Edvard, Sander |
| Poland | 18 | March | Aleksander, Anzelm, Boguchwał, Cyryl, Edward, Narcyz, Narcyza, Salwator |
| Poland | 20 | March | Aleksander, Aleksandra, Ambroży, Anatol, Bogusław, Cyriaka, Eufemia, Klaudia, Patrycjusz, Ruprecht, Wasyl, Wincenty |
| Lithuania | 27 | March | Aleksandras, Alkmenas, Lidija, Ruta |
 Estonia | 19 | April | Aleksandra, Allo, Aalike, Alli, Andra, Sandra |
| Poland | 24 | April | Aleksander, Aleksy, Egbert, Erwin, Erwina, Fidelis, Grzegorz, Horacjusz, Horacy |
| Poland | 3 | May | Aleksander, Antonina, Maria, Mariola, Świętosława |
 Bulgaria | 17 | May | Aleksi |
| Poland | 18 | May | Aleksander, Aleksandra, Alicja, Edwin, Eryk, Eryka, Feliks, Irina, Liboriusz, Myślibor, Wenancjusz |
| Croatia | 27 | June | Ladislav kralj, Ciril Aleksandrijski |
| Poland | 10 | July | Aleksander, Amelia, Aniela, Filip, January, Radziwoj, Rufina, Samson, Sylwan, Sylwana, Witalis |
 Latvia | 17 | July | Ainars, Aleksejs, Aleksis |
| Lithuania | 17 | July | Aleksas, Darius, Girenas, Vaiga |
| Poland | 17 | July | Aleksander, Aleksy, Andrzej, Bogdan, Dzierżykraj, Januaria, Julietta, Leon, Marceli, Marcelina, Maria Magdalena |
| Poland | 11 | August | Aleksander, Herman, Ligia, Lukrecja, Włodzimierz, Włodziwoj, Zula, Zuzanna |
| Croatia | 26 | August | Aleksandar |
| Lithuania | 26 | August | Aleksandras, Alginte, Gailius, Zefirinas |
| Poland | 28 | August | Adelina, Aleksander, Aleksy, Augustyn, Patrycja, Sobiesław, Stronisław |
| Bulgaria | 30 | August | Aleksandar, Aleksandra, Aleko, Sasho, Sashka |
 Finland | 11 | September | Santeri, Aleksanteri, Santtu, Aleksandra, Ale, Ali, Sandra |
| Poland | 13 | September | Aleksander, Aureliusz, Eugenia, Filip, Lubor, Materna, Morzysław, Szeliga |
| Finland | 10 | October | Aleksi, Aleksis |
| Latvia | 8 | November | Agra, Aleksandra, Sandors, Sandra |
| Latvia | 18 | November | Aleksandrs, Brive, Doloresa |
| Bulgaria | 23 | November | Aleko, Alexander, Alexandra, Aleksandar, Aleksandra, Tsanko, Tsanka |
| Croatia | 25 | November | Katarina Aleksandrijska |
| Poland | 12 | December | Adelajda, Aleksander, Dagmara, Paramon, Suliwoj |