Open textbooks are textbooks that have been funded, published, and licensed to be freely used, adapted, and distributed.
- Open Textbooks for Engineering - Engineering Library Division of the ASEE. Provides a list of open textbooks by engineering discipline
- OpenStax College - Peer-reviewed. Openly licensed. 100% free.
- Open Textbook Library - Center for Open Education, University of Minnesota
- BC OpenEd - A curated collection of open textbooks, many reviewed by British Columbia faculty.
- American Institute of Mathematics - A list of open textbooks in various subdisciplines of Mathematics approved by the AIM editorial board.
- OASIS - Openly Available Sources Integrated Search (OASIS) is a search tool that aims to make the discovery of open content easier. OASIS currently searches open content from 97 different sources