Feasts in the Syriac Orthodox Church are divided into two classes: moronoyotho, or feasts pertaining to the Lord (e.g., Christmas, Easter), and dukhronos, or commemorating the Virgin Mary and the Saints.

Some feasts are movable, i.e., their dates vary from one year to another (e.g., Easter). Others are immovable, i.e., their dates are fixed (e.g., Christmas). For the movable feasts, the Church employs the Julian Calendar; for this reason, the date of Easter differs from that of Western Easter. For the immovable ones, the Church has been employing the modern Gregorian calendar since the 1950s. (Note: The Syriac Orthodox Church in Malankara employs the Gregorian calendar even in movable feasts since 1953.)

Fixed Feasts

January
• 1st: Circumcision of the Lord; Sts. Basilius the Great and Gregorius of Nyssa, Doctors of the Church.
• 6th: Baptism of Christ (Epiphany).
• 7th: John the Baptist.
• 8th: St. Stephen, Head of the Deacons and First Martyr.
• 15th: Holy Virgin Mary of the Sowing.

February
• 2nd: Presentation of the Lord in the Temple and St. Simon the Elder (Mor Shem`un Sobo).
• 3rd: Mor Barsowma, Head of the Anchorites.
• 13th: Patriarch Mor Ignatius Elias III.

March
• 9th: The Forty Martyrs of Sebastia.
• 25th: Annunciation to the Holy Virgin Mary.

April
• 23rd: St. George (in the Churches in the East, i.e., Iraq, on the 24th).

May
• 12th: Mor Ya`qub of Nisibin (+338).
• 15th: Holy Virgin Mary of the Harvest.

June
• 15th: Commemoration of the First Church named after the Holy Virgin Mary.
• 29th: Sts. Peter and Paul.
• 30th: All Saints; Mor Ya`qub Burd`ono.

July
• 3rd: St. Thomas.
• 15th: Mor Quryaqos and his mother Yuliti, Martyrs.
• 30th: [Maphryono Bar `Ebroyo].

August
• 6th: Transfiguration of Christ.
• 15th: Assumption of the Mother of God.

September
• 7th: Birth of Holy Virgin Mary.
• 14th: Exaltation of the Cross [Consecration of H.H. Mor Ignatius Zakka I Patriarch].

October
• 2nd: Maphryono Mor Baselius Yaldo.
• 7th: Sts. Sargis and Bachus.
• 15th: Mort Shmouni and Mor Osyo.

November
• 2nd: Mor Gregorius Gheevarghese (Parumala).
• Mor Jacob the Dismembered (mfasqo).

December
• 10th: Mor Behnam, his sister Sarah, and his companions, the forty martyrs.
• 25th: Christmas.
• 26th: Glorification of Holy Virgin Mary at the Lord's Birth.
• 27th: Slaughter of the Children of Bethlehem.

Movable Feasts

• St. Severius, Patriarch of Antioch: The Thursday after the Fast of Nineveh.
• St. Ephrem the Syrian, St. Theodorus the Martyr: The First Saturday in lent.
• Elevation of the Cross, King Abgar, Martyrs of the Syriac Church: The Wednesday at mid-Lent.
• Palm Sunday: The Sunday prior to Easter Sunday.
• Naheere: The evening of Palm Sunday.
• Maundy Thursday and Washing of the Feet: The Thursday of Passion Week.
• Good Friday: The Friday of Passion Week.
• Easter Sunday: This date of this feast has a special computation and all other movable feasts depend upon it. The feast includes the following Monday and Tuesday.
• Confessors: The Friday after Easter.
• Ascension: The Thursday of the fifth week after Easter.
• Mor Barsawmo, Bishop of Kfartooth, Martyr: Thursday before Pentecost.
• Pentecost: The Eighth Sunday after Easter.
• Advent: The period of eight weeks before Christmas.

NOTE. The 1933 Synod of Hums declared that local saints' feasts are to become commemorations except in the respective local churches. These are not listed above.

The Syriac Orthodox Church also observes six fasts every year.

Source:

Patr. Afram Barsoum (trans. V. Rev. Joseph Tarzi), The Spiritual Treasure on Canonical Prayer (Archdiocese of the Syrian Orthodox Church in the Western US, 1999).