Situated at the intersection of language rights, nation-building processes, and security issues, this article analyzes language policies in Ukraine in the three decades since its independence (1991–2021). It traces the legal evolution and decisions of the Ukrainian Constitutional Court, identifying the specific ideological approaches towards language issues that emerge in such a development. We distinguish four periods in the evolution of Ukrainian laws, highlighting how these stages reflect specific ontological and societal (in)securities and related securitization processes, and their intersection with the process of nation-building and the role assigned to the Ukrainian language in such a process. In this way, the article discusses how, in light of the Soviet legacy and Russian kin-state activism and geopolitical agenda, Ukraine has moved to adopt a more assertive nationalizing approach to language issues that aim at promoting Ukrainian as the state language. Russia’s aggressive actions accelerated the ongoing nation-building process, interplaying with the relevance assigned to the Ukrainian language for the Ukrainian nation-state as well as the country’s ontological and societal (in)securities. In this way, our contribution complements our understanding of language policies, bringing to light the connections of their evolution and variations with how security concerns affect nation-building processes.