Most people named Yiannis keep their name day on January 7, the feast of John the Baptist. The Orthodox calendar has 8 other feasts for the name.
Every feast on which Yiannis is celebrated
| New Calendar | Feast | Old Calendar (civil date) |
|---|---|---|
| January 7 | John the Baptist | January 20 |
| January 27 | John Chrysostom | February 9 |
| February 24 | Finding of the Head of St. John the Baptist | March 9 |
| March 30 | John Climacus | April 12 |
| April 19 | John of the Ladder | May 2 |
| May 8 | John the Theologian | May 21 |
| May 27 | John the Russian | June 9 |
| June 24 | Nativity of John the Baptist | July 7 |
| August 29 | Beheading of John the Baptist | September 11 |
The saints behind the name

John the Baptist
January 7, Great Feast, Ιωάννης ο Πρόδρομος
On the day after Theophany, the Church gathers to honor St. John the Forerunner and Baptist, the greatest of the prophets, who was found worthy to baptize the Lord in the Jordan. Son of the priest Zacharias and the righteous Elizabeth, John lived in the wilderness in fasting and prayer, preaching repentance and preparing the way of the Lord.
Name days: Ioannis, Giannis, Yiannis, Yannis, Yanni, Giovanni, John, Jean, Juan, Ivan, Vanya, Yianni, Gianni, Giannakis, Prodromos, Johnny, Ioanna, Gianna, Yianna, Giannoula, Joanna, Joanne, Joan

John Chrysostom
January 27, Great Feast, Ιωάννης Χρυσόστομος
St. John Chrysostom, the Golden-Mouthed, was born in Antioch in the fourth century. First a monk and then a priest famed for his preaching, he was taken to Constantinople and consecrated its Archbishop. He preached constantly on the Scriptures, gave generously to the poor, and fearlessly rebuked the luxury and injustice of the powerful, for which he was twice driven into exile, dying with words of thanksgiving, glorifying God for all things.
Name days: Ioannis, Giannis, Yiannis, Chrysostomos, John, Chrysostom

Finding of the Head of St. John the Baptist
February 24, Great Feast, Εύρεσις Κεφαλής Προδρόμου
This feast commemorates the First and Second Findings of the honorable head of St. John the Forerunner. According to tradition, after the Baptist was beheaded by Herod his head was hidden, and in later generations it was revealed and recovered by the faithful; in times of persecution it was concealed again and found anew, each recovery received with rejoicing and accompanied by healings.
The other feasts are listed in the table above, each with a link to the saint’s life.
Also celebrating on January 7
These names share the feast, many of them other forms of the same name:
Ioannis, Giannis, Yannis, Yanni, Giovanni, John, Jean, Juan, Ivan, Vanya, Yianni, Gianni, Giannakis, Prodromos, Johnny, Ioanna, Gianna, Yianna, Giannoula, Joanna, Joanne, Joan
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.