This paper is devoted to the prospects for sustainable socio-economic development in the context of military-economic cyclicality, first – in the context of the deployment of crisis-militaristic phases of global cycles. Logical and historical methods, dialectical ascent from the abstract to the concrete, including general scientific methods of analysis and synthesis, induction and deduction applied in author’s research. Author substantiated that crisis-militaristic phases are the culminating ones in the development of military-economic cycles; their completion determines the nature of further development of the geopolitical system. In the process of crisis-militaristic phases, the aggravated inter-class, inter-country, inter-civilizational contradictions are partially resolved. After their end, there comes a period of relative stability in the development of the world-system, which is ensured by the fact that the winning social organism in the another large-scale war – a country or a military-political alliance of countries – temporarily establishes institutional practices of societal life at the local and global levels for other actors of the world-system. Periods of relative stability in the cyclical development of the world-system are the time of formation and accumulation of internal contradictions, which creates grounds for the deployment of crisis-militaristic phases of military-economic cycles in the form of “global” wars that stop or slow down those constructive societal processes that bring sustainable socio-economic development closer. The article presents an original formulation of the problem of sustainability of socio-economic development in the conditions of military-economic cycles deployment. The key cycle-forming role of crisis-militaristic phases of military-economic cycles and their impact on the sustainability of the world-system development were identified: it is cyclically disrupted by economic crises and wars, after the completion of which the global geopolitical system is reformatted, new institutional practices of international relations, economic activity, cultural and ideological guidelines are established for a long-term period, which ensures relatively sustainable development.