The purpose of this dissertation is to analyse the popularity of brand communities among Generation Y. The researcher firstly deeply defines, through a critical literature review, the main concepts of this dissertation such as brand community and Generation Y characteristics and culture. The last part of the literature review offers a linkage between the both concepts. The research involves two types of researches. The first one is the quantitative research which has been conducted through a questionnaire survey among Generation Y. The questionnaire analyses Generation Y participation in brand communities: What is the level of participation, for which type of brands and why. The second one is the qualitative research. Generation Y interviews were set up in order to bring a deep understanding of the reasons why Generation Y participates in brand communities, what is their degree of involvement and how they interact within their brand community. Results show that brand communities are popular among Generation Y. One third of the population studied is already involved in a brand community and almost 40% project to join one or more brand communities. Moreover, results demonstrate that Generation Y is particularly interested in IT brand communities. The value/originality of this study is that it was made among Generation Y. Indeed, there already exists several studies on brand communities but during her researches for the literature review, the researcher hasn't found any study who relates to Generation Y and brand communities. This dissertation also offers a fresh view of brand communities.