World Wide Encyclopedia of Christianity
- Links to the contents of the Catholic Encyclopedia, Easton's Bible Dictionary, Torrey's Topical Textbook, Elwell's Dictionary of Christian Theology, and other sources.
- http://www.ccel.org/search?category=definitions

Ilumina
- An interactive Bible and Encyclopedia Suite, from Tyndale House Publishers. Features computer animation and virtual-reality tours.
- http://www.ilumina.com/

World Christian Database
- Statistical information on world religions, Christian denominations, and people groups. Based on the 2600-page World Christian Encyclopedia and World Christian Trends. A full-time staff at The Center for the Study of Global Christianity updates and mai
- http://www.worldchristiandatabase.org/

Thelemapedia
- Explore hundreds of topics in this open source encyclopedia dedicated to the religion of Thelema.
- http://www.thelemapedia.org

Global Anabaptist Mennonite Encyclopedia Online
- Information on Anabaptist-related (Amish, Mennonite, Hutterite, Brethren in Christ) topics, source documents, and history.
- http://www.gameo.org/

Christian Cyclopedia
- Electronic version of the one volume print resource from Concordia Publishing House of The Lutheran Church-Missouri Synod. Includes history, theology, and biographies from within Lutheranism, general Christianity, and non-Christian beliefs.
- http://www.lcms.org/ca/www/cyclopedia/

Jewish Encyclopedia
- Contains the complete contents of the 1906 Jewish Encyclopedia. Over 15,000 articles and pictures about the Torah, history, literature, biography, geography, genealogy, and theology. Accessible for free and full-text searchable.
- http://www.jewishencyclopedia.com/

Cyclopaedia of African Methodism
- An encyclopedia of the African Methodist Episcopal Church, published in 1882.
- http://docsouth.unc.edu/church/waymancyc/menu.html

Centennial Encyclopaedia of the African Methodist Episcopal Church
- Compiled by Richard R. Wright, Jr. Reference work published in 1916.
- http://docsouth.unc.edu/church/wright/menu.html

Early Church Online Encyclopedia
- Hypertext encyclopedia of the early Christian Church up to the Reformation.
- http://www2.evansville.edu/ecoleweb/

Spiritual Encyclopedia
- Covering the most important topics for all spiritual traditions and paths on your way to god. Brief but comprehensive explanation of divine words and principles governing the creation.
- http://www.kriyayoga.com/english/encyclopedia/encyclopedia.htm

Divine Digest
- A quick reference guide to the major World Religions.
- http://www.divinedigest.com/default.htm

Indian Christianity
- Provides information/research aids for Christianity in India, through St Thomas Christian Encyclopaedia of India, and the Indian Church History Classics.
- http://www.indianchristianity.com