Open universities face an unprecedented future of uncertainty, competition, disruption, and mission ambiguity. Many institutions are considering a strategic reset and restructuring of their primary missions to become more responsive and agile in meeting the needs of employers, students, and funding reductions, as well as a competitive landscape dominated by online delivery and innovations in AI. This article argues for the creation of a formal taxonomy for classifying different types of open universities. Stated more succinctly, the author argues that an open university taxonomy would provide greater mission clarity; realignment with societal, government and employer needs; reassessment of the institutional credential continuum; a catalyst for targeting key market niches within a national footprint; alternative funding and budgeting models; and improved academic quality. In conclusion, a taxonomy would serve as a vital catalyst for improving communication among open universities and leaders, expanding strategic thinking about market differentiation, and promoting innovations and partnerships that will benefit all open university stakeholders. [Note: The page range (50-63) shown on the PDF is incorrect based on the page count.]