Highly mobile people (HMPs), such as international executives, airline crew, international sportspersons and independent travellers require flexible, reactive service delivery due to their regularly changing location and activities and the lack of a wired network connection. A mobile service delivery system should be able to detect relevant events such as change of location, sales opportunities and safety issues and then reactively take action in response to those events. This paper describes a generic mobile situation management ontology that was developed in the Ontology Language for the World Wide Web (OWL) using the ontology development tool, Protégé. This ontology can be used as the basis for the development mobile situation oriented service applications.