Father's Day
Father's Day, is observed on the feast day of Fathers. It is celebrated as a public international day, like in many other countries including the U.S., on the third Sunday of June.
In Greece, like in other European countries, this day is named (Fête des Peres/Feast of Fathers)
Mother's Day
The modern Mother's day began in the United States, at the initiative of Ann Reeves Jarvis in the early 20th century. This is not (directly) related to the many traditional celebrations of mothers and motherhood that have existed throughout the world over thousands of years, such as the Greek cult to Cybele, the Roman festival of Hilaria, or the Christian Mothering Sunday celebration (originally a commemoration of Mother Church, not motherhood). However, in some countries, Mother's Day is still synonymous with these older traditions.