Trinity XXI is one of the regular Sundays in Trinitytide, with few to no variations on the standard ritual notes for Sunday masses.

The liturgical color is green.

The mass setting is Merbecke for the Kyrie, Sanctus, Benedictus and Agnus Dei. Old Scottish Chant is used for the Gloria.

The Proper of the mass is at DWM pg. 536.

The Preface is one of the three choices for Preface of the Lord's Day (DWM Pg.s 576-581)

The deacon reads the Prayers of the People using Form III (See DWM pg. 1050).