All Saints’ Day is a solemn holy day of the Catholic Church celebrated annually on Nov. 1, the day after Halloween.
According to catholic.org, “The day is dedicated to the saints of the Church, that is, all those who have attained heaven. It should not be confused with All Souls’ Day, which is observed on Nov. 2, and is dedicated to those who have died and not yet reached heaven.”
All Saints’ Day is a Catholic Holy Day of Obligation, meaning all Catholics are required to attend Mass on that day, unless they have an excellent excuse, such as serious illness.