- Apollo - A knowledge modelling Java application developed by the Knowledge Media Institute. Internal model is build as a frame system conformant to OKBC protocol. Version 1.1 supports OWL.
- Distributed Ontology Management Environment - DOME is developed by the Ontology Management Working Group. The aim is to provide tooling support for editing, browsing, versioning, evolution, mapping and merging of ontologies.
- Dumpont - A simple web service allowing to display class and property hierarchies from a DAML or OWL file.
- EON2002 - Evaluation of Ontology-based Tools - Program and Proceedings of OntoWeb-SIG3 Workshop at the 13th International Conference on Knowledge Engineering and Knowledge Management.
- F-OWL - An ontology inference engine for OWL, using Flora-2, an object-oriented knowledge base language and application development platform.
- IBM Ontology Management System - A framework for loading ontologies from files and via the Internet and for locally creating, modifying, querying, and storing ontologies.
- Ontolingua - A distributed collaborative environment to browse, create, edit, modify, and use ontologies. Provided by the Knowledge Systems Laboratory of Stanford University.
- Ontology Building: A Survey of Editing Tools - Survey of ontology editing tools summarizes more than 50 software tools and provides a brief introduction to the topic. Includes resources.
- Ontology Works, Inc. - Makers of ontology engineering tools for enterprise information integration.
- Open Cyc - OpenCyc is the open source version of the Cyc technology, the world's largest and most complete general knowledge base and commonsense reasoning engine.
- OWL Ontology Validator - An on-line tool that identifies an ontology as OWL Lite, OWL DL, or OWL Full.
- Pellet OWL Reasoner - An on-line tool providing various reasoning services for OWL documents, such as OWL species, consistency checking, satisfiability, entailment test.
- pOWL - pOWL is web-based knowledge base edititing and management solution for the Semantic Web. It supports collaborative browsing, querying and editing of RDFS/OWL Ontologies and exposes an API for PHP programmers.
- Protégé - A free open-source Java tool providing an extensible architecture for the creation of customized knowledge-based applications. Includes documentation, events and publications.
- RACER System - A Semantic Web inference engine for developing ontologies and query answering over RDF, RDFS/DAML or OWL.
- The Chimaera Ontology Environment - A merging and diagnostic ontology environment. It is distributed for external use and has been used in academics and also commercially.
- WordMap Taxonomy Management Software - Allows an organisation to ensure semantic interoperability of metadata, through consistent terminology in all of its applications, assets and activities.
