HermiT is a reasoner for OWL 2 ontologies that supports all of the OWL 2 DL standard. It is a free and open source reasoner developed by the University of Oxford and the University of Ulm. It is based on Java and can be controlled using the OWL API, Protégé, or via command line. HermiT is available under the LGPL 3.0 license. HermiT runs on all operating systems that support Java 1.6 or above.

HermiT originates from the Information Systems Group of the University of Oxford, where Birte Glimm was part of the development team. She still continues her involvement in HermiT after moving to the University of Ulm.

More information about HermiT can be obtained from HermiT's web page.