The Holy Trinity Cathedral (Greek: Καθεδρικός και Ενοριακός Ιερός Ελληνόρρυθμος Καθολικός Ναός Αγίας Τριάδος) also called Greek-Catholic Cathedral of Athens is a Greek Byzantine Catholic cathedral in Athens, Greece.

It functions as the seat of the Greek Catholic Apostolic Exarchate of Greece (Exarchatus Apostolicus Graeciae) that was created on June 11, 1932 by the then Pope Pius XI, and follows the Byzantine Rite,

It is under the pastoral responsibility of Bishop Manuel Nin.

• Greek Byzantine Catholic Church
• Roman Catholicism in Greece
• Holy Trinity