The next upcoming Orthodox Easter also called Pascha or Easter Day is celebrated/ observed on Sunday April 8th, 2018. This day celebrates Jesus' resurrection. The day is not a public holiday and always falls on a Sunday so government and business offices that are normally open on this day will remain open. Orthodox Good Friday is the Friday before Easter Sunday and commemorates the Crucifixion of Jesus Christ. The birth of Jesus Christ is celebrated on Orthodox Christmas Day on the Gregorian calendar date of around January 7th each year.
Many Orthodox Christians will do a fast called the Great Lent starting 40 days prior to Easter Sunday and will attend church sessions during Holy Week that lasts 7 days prior to Easter Sunday.
Some in the Orthodox church use the Julian calendar to determine Easter versus the Western church using the Gregorian calendar to determine Easter. Because of the use of different calendars this causes Easter Sunday in some of the Orthodox church to often fall later in the year than the Western Church however sometimes Easter will fall on the same day. Eastern Orthodox churches celebrate Easter the first Sunday after the first full moon of Spring and also must be after the celebration of Passover. Easter for the Orthodox church that uses the Julian calendar to determine their holy days will always fall sometime between April 4th and May 8th each year.