The article analyzes the relevance of diversification processes for the modern military-industrial complex of the Russian Federation and the difficulties that domestic enterprises face on the path to their deployment. The relevance of the study is due to the role that the military-industrial complex (MIC) plays for the future of the country in general and for its economic dynamics in particular. The study uses modeling methods when forming a model for constructing the interaction of a large regional defense industry enterprise and the external environment, analysis to substantiate the effectiveness of the development of diversification processes implemented in the defense industry enterprise, a scenario approach, when predicting the development of diversification processes based on the object of study and determining its inertial, optimistic and pessimistic development scenarios. It is noted that increasing the production of civilian and dual-use products can become a guarantor of long-term operation for defense enterprises, as well as a path to ensuring their own technological sovereignty and contribution to the technological sovereignty of the country. The question is raised about the optimal way to build integration interaction between defense industry enterprises and other economic entities along the path of diversification processes. The concept of entrepreneurial ecosystems is proposed as the basis for such interaction. A model is presented for the formation of an entrepreneurial ecosystem in the military-industrial complex with the participation of local development institutions, industrial partners, universities, and small and medium-sized businesses. Using a particular example, a conclusion is drawn about the economic feasibility of introducing this model. The obtained materials can be useful to defense industry enterprises in the process of developing programs for the diversification of military production and the development of dual-use technologies.