The book discusses discrimination based on sexual orientation in the jurisprudence of the European Court of Human Rights (ECtHR) and the Constitutional Court of Korea. The work provides insights into how prohibition on discrimination based on sexual orientation can be realized in South Korea with the reference of the case law of other jurisdictions including mainly from the ECtHR. The book reviews related principles and methodological tools applied in the jurisprudence of the ECtHR. Considering that the rights of sexual minorities are evolving in many jurisdictions including Europe, and this problem is currently of great importance in the constitutional and political discussion, the topic is important to the readers in Europe as well as in Korea.