Measuring satisfaction can provide developers with valuable insight into the usability of a product as perceived by the user. Although such measures are typically included in usability evaluations, it is clear that the concept itself is under-developed. The literature reveals a lack of cumulative, systematic research and consequently the field is in “disarray” (Hornbæk, 2006). Clearly, the area needs a strong theoretical foundation on which to base research. This paper reviews the literature on user satisfaction and proposes a conceptualisation and definition of the concept that will aid researchers in the development of valid measures.