Most people named Giannis keep their name day on January 7, the feast of John the Baptist. The Orthodox calendar has 10 other feasts for the name.
Every feast on which Giannis is celebrated
| New Calendar | Feast | Old Calendar (civil date) |
|---|---|---|
| January 7 | John the Baptist | January 20 |
| January 27 | John Chrysostom | February 9 |
| January 30 | Three Holy Hierarchs | February 12 |
| April 19 | John of the Ladder | May 2 |
| May 8 | John the Theologian | May 21 |
| May 25 | Third Finding of the Head of John the Baptist | June 7 |
| June 24 | Nativity of John the Baptist | July 7 |
| August 29 | Beheading of John the Baptist | September 11 |
| September 26 | Repose of the Evangelist John the Theologian | October 9 |
| November 12 | John the Merciful | November 25 |
| November 13 | John Chrysostom (repose) | November 26 |
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

Three Holy Hierarchs
January 30, Great Feast, Τρεις Ιεράρχαι
The feast of the Three Holy Hierarchs honors together Sts. Basil the Great, Gregory the Theologian, and John Chrysostom, the great fathers and ecumenical teachers of the Church. According to tradition, the common feast was established in the eleventh century after disputes arose in Constantinople over which of the three was greatest; the hierarchs made known in a vision that they are one before God, and a shared commemoration was appointed.
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, Yiannis, 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.