This book implies the perspective of modern natural law concepts in thinking about the ECtHR judgements on same-sex marriage in a philosophical way. in this interpretation, decisive concepts and theories of forerunner scholars, who are Lon Fuller and Ronald Dworkin, in modern natural law philosophy are used in the light of perspectives enhanced by these natural law philosophers.2 in this line, why they are selected for this purpose is their pivotal place in the realm of modern natural law philosophy, which has emerged from the 20th century until present. in this stage, it might be asked why modern natural law is more qualifıed than traditional natural law for intended reasoning? To answer this d question, it is crucial to deeply understand the differences between them.