There is growing interest in the development of context-aware ubiquitous systems which can support seamless computing for mobile users in integrated, heterogeneous environments built from a variety of network technologies, sensors and computing devices. In addition, there is growing interest in context-aware applications that intelligently support user tasks by acting autonomously on behalf of users in these integrated, ubiquitous environments. However, there is also increasing recognition of challenges associated with context-awareness, including barriers associated with scalability and usability and novel software engineering problems. This workshop focuses on context models that provide abstractions to foster context reuse and ease of programming, and support development of scalable, robust, reliable and usable context-aware applications. The workshop also responds to the growing popularity of ontology principles and methods in ubiquitous computing systems, and examines the role that these can play in context modelling and reasoning about context. This workshop offers the opportunity to bring together researchers involved in the development of context models and context-aware applications for ubiquitous computing environments. It aims at exploring the most recent research results and ongoing work in the areas of context modelling, reasoning about context, and management of context information. Special emphasis will be placed on presenting state of the art and emerging research as well as experience reports.