Self-determination has long been recognised as an inherent right of people. However, with the lack of a detailed provision on what defines the right and how it may be invoked, the struggles and conflicts in invoking the right to self-determination had never ceased nor diminished. With the raising threats of terror, many of the struggles had been labelled as a form of terrorism by certain states. This is also due to an absence of a universally accepted definition of the term terrorism. The purpose of this study is to address the legal criteria of self-determination in relation to terrorism under international law and to examine legal patterns that construed self-determination in existing and past situations. The study employs a doctrinal method of research based on Article 38 of the Statute of the International Court of Justice. It will analyse the existing legal provisions and juristic opinions on matters concerning the right to self-determination and terrorism. The result of this study reveals that there are legal patterns and criteria that can be traced in all struggles of self-determination, either successful or not. This can be used as a demarcating factor of the grey area between selfdetermination and terrorism