A tribunal is the Church's court of justice. From a practical standpoint, a tribunal functions principally in the investigation of marriage nullity cases, applying the Church’s laws found in the 1983 Code of Canon Law.

As the compassionate arm of the Church, a tribunal is where rights are upheld and justice is rendered in judicial matters pertaining to ecclesiastical law. Its primary concern of investigating marriages, i.e., to discover whether they were invalid (the presumption is a marriage is valid), is for the spiritual well-being of the parties.