The article examines the theoretical and practical effects of wars in the 21st century on the economy. The concept of “military economy” is highlighted. The dynamics of military expenditures are analyzed. The reasons behind and types of wars that have occurred in the past and are currently occurring are made clear. Emphasis is placed on studying the economic consequences of Russia’s war in Ukraine. The assessment of the potential of countries before the war testified and confirmed the aggressive goals of a large country that attacked a much smaller one. The war against Ukraine put the issue of preserving the independence of small countries on the agenda. The main focus of the essay is on examining the economic effects of the conflict, not just on the economies of the participating nations but also on the world economy. The instability of individual commodity markets, inflation, and migration became the main mechanisms of the war’s influence. As a result, the indicators of economic growth of many countries of the world are deteriorating. The raised questions actualize the task before the world community of finding new methods of solving the problems of wars.