As a result of the full-scale Russian invasion, Ukraine’s economy underwent structural changes, which negatively affected the dynamics of its development. The field of the startup entrepreneurship had a high level of sustainability due to unique, innovative ideas and solutions in conditions of uncertainty. Developing innovative enterprises and expanding global investment resources are the foundations of Ukraine's innovative growth. However, putting this into action is an exceptionally difficult challenge for the state. The study of trends in the development of startup entrepreneurship in martial law conditions, the analysis of the sources of their financial support, and the development of effective solutions to regulate their functioning show the article's relevance. Many scientists have dealt with the issues of regularities of development and the basics of the functioning of startups in Ukraine. Despite significant scientific progress, the financial aspects of supporting startup entrepreneurship in wartime conditions still need to be explored. The article aims to study the trends in the development of start-up entrepreneurship under martial law, analyze the main sources of their financing, and develop recommendations for improving the financial support of start-up entrepreneurship in Ukraine. The article examines the process of origination and development of startup entrepreneurship in the domestic economy. It identifies six stages of its formation: origination, growth, adaptive stage, the newest stage, the current stage, and the period of martial law. The author analyzed the dynamics of the development of startup entrepreneurship within the country and determined the rating position of Ukraine in StartupBlink of the world's ecosystems, in selected cities that act as locomotives for the development of startup entrepreneurship in the country. Based on the analytical reports of Startupranking, a negative trend of startups development during wartime was revealed, which is explained by limited access to the capital of financial organizations and new sources of financing. According to the Ukrainian Startup Fund, the article reviews current programs to support the development of startup entrepreneurship. It investigates the financial support of international organizations for this type of business.