This thesis is a study of Facebook users? beliefs attitudes and behaviour towards personalised adverts on the site, using Wang & Suns theory about the relationship between beliefs and attitude toward online advertising (ATOA) and the connection between attitude and behaviour. The result, based on qualitative research and interviews, will introduce a deeper understanding and interpretation of users? beliefs, attitudes and behaviour toward personalised adverts. The result showed that people perceive the site?s personal adverts as intrusive and interfering with their personal space and the purpose of the site.