Olga’s name day is July 11, the feast of Olga of Kiev.
Churches that follow the Old (Julian) Calendar keep the same feast on July 24 of the civil calendar. See everything commemorated on July 11.
The saint behind the name
Olga of Kiev
July 11, Apostle, Όλγα
St. Olga was the wife of Prince Igor of Kiev and ruled Rus' after his death in the tenth century. She traveled to Constantinople, where she was baptized with the name Helen, and returned to Kiev as the first Christian ruler of her people.
Also celebrating on July 11
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.