A Proposal to Expand the Sunday Lectionary outlines how to increase Scripture readings at Sunday Mass in the Latin Rite of the Roman Catholic Church by expanding the current three-year cycle to a four-year cycle. The proposed fourth year, Year D, would focus on the Gospel of John-complementing Years A, B, and C, which are based on Matthew, Mark, and Luke, respectively. This draft builds upon A Proposal to Expand the Weekday Lectionary, which suggested reading the entire Bible in a ten-year weekday cycle during Ordinary Time.

As in the earlier proposal, the liturgical calendar remains unchanged. The structure of the Liturgy of the Word is preserved: a Gospel reading at every Mass, a First Reading followed by a Responsorial Psalm, and on Sundays and feast days, a Second Reading before the Gospel.

Across the four-year Sunday cycle, all verses from John and Mark's Gospels would be read, and the Acts of the Apostles would be proclaimed in full during the Easter season. Bishops, clergy, liturgists, and others interested in deepening engagement with Sacred Scripture at Sunday Mass will find this proposal thoughtful, enriching, and timely.