This study aims to examine the phenomenon of multiculturalism and socio-cultural conflicts in United Kingdom. In fact, the concept of multiculturalism as the belief and practice of giving equal importance to each of the different culture in a society is a doctrine that recognizes ethnic diversity within a society and that encourages others to be enlightened by those of diverse ethnical and cultural background. The consequences of the socio-cultural conflicts handicap the success of this phenomenon, not only in the United Kingdom but all over the world. So, this study is significance since it can draw the attention of people on the studied phenomenon which remains nowadays the basic factor of most conflicts in the world.