The number of Muslims in Western Europe ranges from 12 to 15 million, which makes Islam the second largest religion in Europe and the fastest growing religion in the case of the US. However, the future of European Muslims depends on their ability to correctly understand Islam and behave in a way that reflects Islam and the values of their societies. The interference of Muslims outside Europe in the affairs of European Muslims, especially the extremist trends and the armed groups, have an impact on how far Europeans will accept Muslims as full citizens.