[7] His research[3][8][9] focuses on knowledge representation and reasoning, particularly ontology languages,[10] description logic and optimised tableaux decision procedures.

These languages and associated tools have been used by Open Biomedical Ontologies (OBO)[21] Consortium, the National Cancer Institute (NCI) in America, the United Nations (UN) Food and Agriculture Organization (FAO), the World Wide Web Consortium (W3C) [22] and a range of major corporations and government agencies.

[27] In 2020 Horrocks was awarded the BCS Lovelace Medal in recognition of his significant contribution to the advancement of reasoning systems.

[2] In 2017 Horrocks co-founded the University spin-off Oxford Semantic Technologies Limited[28] with two of his colleagues; Bernardo Cuenca Grau and Boris Motik.

[29] “All text published under the heading 'Biography' on Fellow profile pages is available under Creative Commons Attribution 4.0 International License.” --Royal Society Terms, conditions and policies at the Wayback Machine (archived 2016-11-11)