General Formal Ontology (GFO)

  1. Introduction
  2. Documentation and Publications
  3. Axiomatizations and Implementations
  4. Mailing List
  5. Brief History


The General Formal Ontology is a top-level ontology for conceptual modeling, which is being constantly further developed by Onto-Med. It includes elaborations of categories like objects, processes, time and space, properties, relations, roles, functions, facts, and situations. Moreover, we are working on an integration with the notion of levels of reality in order to more appropriately capture entities in the material, mental, and social areas. Outstanding features of GFO are:

  • coherent integration of objects and processes (based on a novel category of persistants)
  • time and space entities as entities sui generis, and the relation of coincidence
  • a category of situoids, comprehensible wholes of the most independent character
  • elaborate accounts of functions and roles
  • openness regarding philosophical positions such as realism, conceptualism, or nominalism by the provision of different kinds of categories as universals, concepts, or symbolic structures
On this page, we provide remarks on and links to GFO documentation, information on axiomatizing and implementing GFO, i.e., downloads, development tools, and the release strategy, a pointer to our mailing list as well as brief historical remarks.

Documentation and Publications

Onto-Med Report Series on GFO

The major descriptive source for GFO is a series of Onto-Med Reports. As this work progresses continuously and in irregular intervals, draft versions are also provided. These may exhibit some technical deficiencies (e.g., few missing references, "empty sections" indicating areas under research). Nevertheless, they best reflect the continuing development of GFO during report releases.

The series comprises reports with respect to three components: Part I (Basic Principles) sets forth the logical and philosophical basic assumptions and methods, and presents a conceptual account of the General Formal Ontology (GFO) in some detail. Part II (Axiomatics and Ontology Languages) presents a full axiomatization of GFO, as well as a library of ontology languages, and several tools for meta-logical analyses of formal axioms. In Part III (Applications) several applications of GFO are collected and presented. So far, only Part I is available, whereas Part II and III are under development.

The following is the general form of citation for Part I, where the corresponding version and, for releases, the number in the series should be added.

Herre, H.; Heller, B.; Burek, P.; Hoehndorf, R.; Loebe, F. & Michalek, H.. General Formal Ontology (GFO): A Foundational Ontology Integrating Objects and Processes. Part I: Basic Principles. Research Group Ontologies in Medicine (Onto-Med), University of Leipzig.

Latest Revisions

  • Latest intermediate revision: Version 1.0.1, Draft, 14.02.2007 [PDF] (changes: primarily sect. 2.3, 3.5, 3.6, 8 and 16)
  • Latest released revision: Version 1.0, Onto-Med Report Nr. 8, 01.07.2006 [PDF] [HTML]

Other Publications Exclusively Presenting GFO

  • Herre, H. 2010. General Formal Ontology (GFO): A Foundational Ontology for Conceptual Modelling , to appear 2010 [PDF]
  • Heller, B. & Herre, H. 2004. Ontological Categories in GOL. Axiomathes 14(1):57-76 Kluwer Academic Publishers. [PDF]
  • Heller, B. & Herre, H. 2003. Formal Ontology and Principles of GOL. Onto-Med Report Nr. 1. Research Group Ontologies in Medicine (Onto-Med), University of Leipzig.

Further Documentation

Apart from the GFO reports, we have not yet completed the work on more introductory or tutorial material. This is going to happen in the nearer future. Currently, the easiest way to access the basic categories of GFO is to view the file gfo-basic.owl in an ontology editor (e.g. OwlSight). In particular, that file provides short descriptions for each category. Moreover, we are aware of the following web sources (external to this site) which cover GFO documentation (on varying levels of recency, detail, and completeness):

Axiomatizations and Implementations

The "native" formalization language for GFO is first-order logic (FOL). Partial axiomatizations of GFO in FOL exist in report working drafts, but are not yet available to the public.


There is an OWL version of GFO, which currently comprises a stable core called gfo-basic.owl and a more extensive version called gfo.owl. The stable URLs to the current releases of these files are:

Release Notes

gfo-basic.owl, version 1.0: Some users have reported problems with the use of the GFO namespace,, as base namespace for gfo-basic. We stick to this convention in gfo-basic.owl, but provide the file gfo-basic-renamed.owl (cloned from gfo-basic.owl, version 1.0 build 13).

Release Strategy

gfo-basic.owl forms the core of the coming releases. We are going to continually provide several extensions to gfo-basic.owl, dedicated to several of our research domains, like time, space, processes, etc. There may be parallel extensions for these domains, and not all extensions will be consistent with each other. All files are provided with the GFO namespace, as their base namespace. All extensions should import gfo-basic.owl. Eventually, a selection of those extensions will be unified in the next version of gfo.owl. Note that the latter has not yet been adapted to gfo-basic.owl.

Release History

Work on the OWL version of GFO started in early 2006 in the context of the GFO-Bio project, resulting in the 1.0 release of gfo.owl. The renewed release strategy in 2008 lead to gfo-basic.owl, a corrected and slightly simplified version.

Development Tools

There is a CVS versioning system hosted as a Savannah project, including a ViewCVS.

In order to link to the latest version of the files (HEAD checkouts), you can use

Mailing List

We invite you to send us your questions or provide feedback on GFO and top-level ontologies in general, experience with using GFO, usability of the available material, etc. Please send a mail to the public mailing list, i.e., address mails to . You may also have a look into the archives.

Brief History

Work on GFO has started in 1999 in the context of the GOL project (General Ontological Language). Meanwhile, several directions of research have been recognized and divided the initial project, such that GFO is now one component of a larger framework. Work on GFO remains in progress, because the development of top-level ontologies is a long-term research effort.