Régi - Ritu
- Regina
- Regina Coeli
- Regina Coeli (Queen of Heaven)
- Reginald Cardinal Pole
- Reginald of Piperno
- Reginald Pecock
- Regino of Prüm
- Regionarii
- Régis, Jean-Baptiste
- Regis, John Francis, Saint
- Régis, Pierre Sylvain
- Registers, Parochial
- Regnault, Henri Victor
- Regulae Juris
- Regulars
- Regulæ Juris
- Reichenau
- Reichensperger, August
- Reichensperger, Peter
- Reifenstein
- Reiffenstuel, Johann Georg
- Reims
- Reims, Synods of
- Reinmar of Hagenau
- Reisach, Carl von
- Reisch, Gregor
- Relation of God to the Universe
- Relationship
- Relatives, Duties of
- Relativism
- Relics
- Religion
- Religion, Virtue of
- Religions, Statistics of
- Religious Communities of the Name of Jesus
- Religious Congregations of the Holy Ghost
- Religious Congregations of the Presentation
- Religious Discussions
- Religious Dower
- Religious Indifferentism
