ENThe Republic of Lithuania is a state that plays an important role in the international community. Although it is not one of the most powerful states, its activity and consistent policy make it a significant player in the international arena. It is noticeable that the role of small states in international relations is growing as a result of changes in the international environment. The result is progressive globalization and collapse of the postcommunist system evolving towards multipolarity. The aim of the article is to analyze the actions taken to build the security of the region in the international arena by Lithuanian foreign policy in the era of the Russian invasion of Ukraine. This article attempts to verify the hypothesis that Lithuania is able to launch a process that can bring benefits to the entire region, and thus contribute to building international peace and security. Keywords: small country, security, diplomacy, NATO, EU, Ukraine, Baltic region, Lithuania.