| ENCYCLOPEDIAS ONLINE | |
| Encyclopedia Britannica | One of the worlds leading encyclopedias, always updated. |
| Encyclopedia of Islam | |
| Oxford Reference Online | 125 reference works from Oxford University Press gathered in one single and useful database. |
| The Catholic Encyclopedia | A bit old, but still useful catholic reference work. |
ENCYCLOPEDIAS IN PRINT | |
| The Anchor Bible Dictionary | Probably the best biblical encyclopedia (6 vols, 1992). |
| The Brill Dictionary of Religion | A good reference work on religion in general (4 vols, 2007) |
| The Encyclopedia of Christianity | English translation of a German encyclopedia on protestant history and theology (5 vols, 1998-2008). |
| The Encyclopedia of Religion | A standard reference work by Mircea Eliade on religions and religious phenomenas (16 vols, 1993). |
| Lexikon für Theologie und Kirche | Important German catholic encyclopedia (12 vols, 1993-2001). |
| New Catholic Encyclopedia | The most important English catholic encyclopedia (15 vols, 2003, 2. ed.). |
| Theologische Realenzyklopädie | The leading protestant encyclopedia, in German (36 vols, 1997-2007). |