Theodosis’s name day is May 3, the feast of Theodosius of the Kiev Caves.
Churches that follow the Old (Julian) Calendar keep the same feast on May 16 of the civil calendar. See everything commemorated on May 3.
The saint behind the name
Theodosius of the Kiev Caves
May 3, Venerable, Θεοδόσιος των Σπηλαίων του Κιέβου
Theodosius was born near Kiev in the eleventh century and, against his mother's wishes, sought out Saint Anthony in his cave above the Dnieper. He became the second abbot of the community and gave it the coenobitic rule of the Studion, building the first great monastery of Rus.
Name days: Theodosios, Theodosius, Theodosis
Also celebrating on May 3
These names share the feast, many of them other forms of the same name:
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.