- Dictionary of Sorts - Philosophical terms mostly from ethics and epistemology, edited by Robert Berman.
- ISCID Encyclopedia of Science and Philosophy - A free, community developed resource containing information on both science and philosophy.
- Larry Hauser's Mostly Modern Philosophical Glossary - Glossary of philosophical terms focusing on modern philosophy.
- Meta-Encyclopedia of Philosophy - A list of philosophical terms and names linked to the major encyclopedias and dictionaries of philosophy on the internet.
- PhiloSophos - Includes philosophy papers, university distance learning programs and college correspondence courses, and a philosophy dictionary.
- Philosophy Dictionaries and Encyclopedias - Collection of links to philosophy reference sources.
- Routledge Encyclopedia of Philosophy - Online edition. Free access to sample contents, full access by subscription.
- Sophia Project - On-line resource for philosophy students sponsored by the Molloy College Department of Philosophy.
- The Ism Book - A dictionary of philosophies from Peter Saint-André, editor of the Monadnock Review.
- Think: Philosophy - Philosophy resource for beginners. Contains philosophers, schools of thought, and topics.
- Wikipedia: Philosophy - The entrance page to all articles in the philosophy section of the free encyclopedia.