The notion and topic of Quality of Experience (QoE) keeps attracting the attention of manufacturers, operators and researchers. It links user perception and expectations on one side and technical Quality of Service (QoS) parameters, management, pricing schemes etc. on the other side. Such links are needed in order to balance user satisfaction and economic aspects of service provisioning. However, the notion of QoE as such is not without controversy. Technicians, used to a world of objective and clearly definable parameters, tend to fear the subjective, somehow fuzzy parts associated with end user perception. Vice versa, customer relationship and marketing departments might find themselves uncomfortable with technical parameters which might not reflect the user perception in some tense situations. Nevertheless, appearance and utility of a networked service depend on the underlying technical solutions and their performance. Thus, we face the challenge of bringing it all together, which essentially describes the spirit of the 18th ITC Specialists Seminar on Quality of Experience (ITC-SS 18). ITC Specialist Seminars have a very good reputation in gathering experts and their high-quality contributions around a performance-oriented topic of mutual interest. ITC-SS 18 is intended as a meeting place between experts, researchers, practitioners, vendors and customers. It is devoted to presentations and discussions of QoE concepts, analysis, management approaches etc., both from industry and academia. While many conferences are dominated by academia, one third of the submissions to ITC-SS 18 originated from industry. The contributions have been peer-reviewed by at least three independent reviewers and finally, we selected 18 papers to be presented. Additionally, two keynote speeches reflect one industrial and one academic approach to QoE analysis and implementation. For the ITC, the leading conference for performance modeling and analysis of communication networks & systems, ITC-SS 18 opens a window towards the end user. ITC-SS 18 takes place in Karlskrona on May 29—30, 2008. It is organized by the Dept. of Telecommunication Systems (ATS) within the School of Engineering (TEK) at Blekinge Institute of Technology (BTH) in cooperation with the International Advisory Council (IAC) of ITC.