Many people often wonder why or even whether there is an apostrophe in Father's Day. There is an apostrophe in Father's Day andthe reason is quite simple. Father's day was meant to celebrate the contribution of a father to his family. Father is not meant as a collective group here. It is a not a day to honor all the fathers in the world. It is a day to celebrate each father as an individual. This is why the apostrophe is after r and before s, so that it indicates that the father is an individual. If the apostrophe was after s, then the meaning completely changes. For example, April Fool's Day is a day for all the fools of the world. That is why the apostrophe is after L. If Father's Day were spelled Fathers' Day, then the holiday would refer to a day for all the fathers in the world to celebrate together. This is why you will see that people wish Happy Father's day to their father only and not to everyone. It is different from other popular days like Christmas Day, where you wish everyone.