One of the key causes of disharmony on a global scale, throughout human history, has been the disregard for the protection of religious expression. This goes some way to explaining why the international community in the post-war era, particularly after World War II, have enacted legal instruments and implemented policies aimed at promoting religious freedoms at global and regional levels. Regionally, the ECHR with implementation mechanisms has led the way in terms of upholding the protection of religious rights and freedoms. Having progressive and effective mechanisms to protect human rights does not mean that decisions of the ECtHR as a judicial body are free of criticism. For example, the ECtHR has ruled in the number of cases against the practice of religious expression, particularly in cases relating to the wearing of the headscarf. These decisions, the ECtHR argues, were taken on the grounds of secularism and prevention of fundamentalism and intolerance. This research, unlike others written on the subject, examines the concepts of fundamentalism and tolerance through a historical and philosophical approach, which will be used to argue that a restriction on the headscarf cannot legally or logically be justified as the bases used by the court to provide a rationale for the rulings are undefined, ambiguous and often in conflict with the principle of religious expression. The ECtHR often prioritises national policies and political considerations such as secularism over the personal right to freedom of religious expression. Notably, recent polices in Turkey which now allow and encourage the wearing of headscarf in public places call into question the validity of previous judgments of the ECtHR supporting the ban on wearing of the headscarf. As a part of the qualitative methodology the researcher has chosen three methods to conduct this research including black-letter, historical and comparative themes. This thesis is critically analysis ECtHR cases relating to freedom of religious expression in the context of the wearing of the headscarf. In doing this thesis further explores the relationship between Article 9 ECHR, the wearing of the headscarf, and the concepts of fundamentalism and intolerance. The researcher argues that the link between the wearing of the headscarf and intolerant or fundamentalist behaviour is a difficult one to prove, and that by supporting the ban on wearing of the headscarf on grounds including intolerance, the ECtHR’s decisions are in effect validating intolerance of religious expression.