As Indigenous scholars committed to Indigenous education in Oklahoma, we use a decolonizing approach to consider how the 39 Indigenous Nations in Oklahoma assert educational sovereignty to sustain Indigenous high school students' linguistic and cultural identities. Seeking to promote education models that sustain and revitalize Indigenous languages, we ask: 1) How do Indigenous Nations in Oklahoma engage in language planning and liberate educational sovereignty through policies, programs, and services to their high school students? and 2) How do Indigenous Nations navigate Oklahoma state education language-in-education policies that may support or restrict Indigenous language education in public high schools? We consider the function of Oklahoma public high school classrooms as sites of Indigenous language revitalization and reclamation. We discuss how Indigenous educational sovereignty to support language revitalization occurs in interaction with overlapping and often competing language-in-education policies imposed by the state of Oklahoma. A goal of this article is to share knowledge with Indigenous Nations, educators, and policy makers who are involved in language planning. We conclude with recommendations of ways to support culturally sustaining and revitalizing education models for Indigenous students, communities, and languages in Oklahoma.