The purpose of the study is to develop the main ontological provisions of the developed theory of soft foreign policy power of the state. Achieving this goal involves solving the following tasks: clarifying the content of the concept, classification of forms and corresponding types of social mechanism and arsenals of the main instruments for exercising the foreign policy influence of a sovereign state at the current historical stage of evolution of the social sphere of life; to clarify the content of the concept and classification of forms of the phenomenon of the foreign policy power of the state, as well as adequate mechanisms and instruments to ensure their functioning; clarifying the content of the concept and the mechanism of existence of the phenomenon of the foreign policy power of the state, the classification of forms of the phenomenon, as well as the composition of resources to ensure their existence. The following general scientific methodological tools were used in the study: historical analysis, comparative analysis, the principle of unity of historical and logical, hypothetical and deductive, cause and effect, generalization, and systematization. The developed system of theoretical provisions differs substantially from the relevant provisions of the “soft power” concept. In this regard, it is proposed to define the system of the research results as a “theory of soft foreign policy power of the state”. The concepts of the complex interdependence of states, foreign policy influence of the state, foreign policy power of the state, foreign policy strength of the state, and resources of foreign policy strength of the state are defined as the basic system-forming categories for the development of a developed theory; its structural elements-complex interdependence of states, soft foreign policy power of the state, soft foreign policy influence of the state, soft foreign policy power of the state. Although the developed knowledge system has ontological, epistemological, and axiological features, it should be recognized as incomplete in the praxeological aspect. In particular, the theoretical issues of assessing the level of soft foreign policy power of the state; assessing the scale of implementation, intensity, and effectiveness of the process of soft foreign policy influence of the state; assessing the scale of coverage and point of soft foreign policy power of the state remain unresolved. These issues should be the subject of further research. [ABSTRACT FROM AUTHOR]