Abstract: The paper studies the system of views and ideas about international public law developed within Protestantism as a cultural phenomenon. The research subject includes the doctrinal developments defining the essence and the content of the protestant concept of international law. The author characterizes the ideas of the central protestant philosophers which the modern concept of international law is based on – Hugo Grotius, Christian Wolff and Emer de Vattel. Special attention is paid to the protestant concept of human rights and the justification of their special nature. To acquire trustworthy scientific results, the author applies the set of general scientific and specific research methods which are complemented with the principles of dialectics: analysis, synthesis, the formal-legal, historical-legal and comparative-legal methods. Particularly, the hermeneutical approach is used to define the content of the provisions of doctrinal developments of philosophers depending on the particular meanings of culture. The contribution of protestant ideas to the development of international law consists in the positivization of international law and its further dehumanization, when a premium is rather placed on an absolute power of the state than on the rights and interests of a person. Ignoring the doctrine of God as a sole sovereign, Positivists authorized only the state with an absolute sovereignty, and this positivist theory of sovereignty turned into an instrument protecting and justifying the violation of personal rights and freedoms within the state. Ultimately, this positivist-protestant concept of international law had led to the inability of international law to resist to humanitarian disasters of the world wars of the 20th century.