Encyclopedias, Almanacs, Transcripts, and Maps
- Instrumental Causality
- Integralism
- Integrity, Gift of
- Intellect, Unity of
- Intellectual Life
- Intellectualism
- Intelligibility, Principle of
- Intention, Purity of
- Interfaith and Ecumenical Family of Organizations
- Interfaith and Ecumenical Family of Organizations: Interfaith Groups
- Interfaith Groups
- Interims
- Intermediate States
- International Association of Jewish Ge-Nealogical Societies
- International Catholic Deaf Association
- International Catholic Migration Commission
- International Catholic Stewardship Council
- International Commission on English in the Liturgy (ICEL)
- International Conference of Jewish Com-Munal Service
- International Consultation on English Texts (ICET)