In the diploma thesis we defend Ontological Security Theory as an equivalent and complementary concept to classical theories in the field of International Relations. The fundamental contribution of Ontological Security Theory is belief that states, in addition to
physical (security-as-survival), pursue ontological security (security-as-being) – the security of the Self. The relevance, contribution and intellectual value of the thesis is demonstrated on two levels: (i) in a theoretical-conceptual framework in an attempt to establish Ontological Security Theory in relation to other theories in International Relations and, further, by an eclectic understanding of Ontological Security Theory and the Theory of Securitization of the Copenhagen school, and (ii) in the empirical part by analyzing the selected Speech-Acts of Turkish President Erdogan. We have shown how Turkey pursue and reproduce its ontological security after a failed coup attempt. Securitized identities of the Self/Other relations become a source of ontological security.