Trust is a key requirement for the successful uptake and operation of Utility and Cloud Computing (UCC). Service consumers must have belief that their data is safe and protected and service providers must provide sufficient assurances to satisfy these beliefs. However many challenges need to be overcome before this is possible. A myriad of trust relationships can arise between the different players in the UCC service delivery chain and these need to be understood and described as do the consequential assurance approaches that may be required. Complex, and varying, UCC service delivery environments may require very different and context dependent mechanisms to provide the assurances needed. This workshop aims to explore approaches to the definition and establishment of trust relationships in a dynamic and evolving UCC service environment and to investigate mechanisms, methodologies and technologies to enable the provision of assurances that are needed to fulfil users trust beliefs. The IWTCC will be held in Limassol, Cyprus in December, 2015 . It provides a forum for researchers world-wide to present their latest work in privacy, security and trust in the cloud, and to show how this research can be used to enable innovation. IWTCC is organized by the Irish centre for Cloud computing and Commerce (IC4) and by The Distributed and intelligent systems (DISYS) research team at the university of Derby.