The analyses presented here are part of a larger project, "Understanding Children's Transitions from Head Start to Kindergarten" (HS2K), a joint research venture between NORC at the University of Chicago, Child Trends, and the National P-3 Center at University of Colorado Denver, with funding from the U.S. Administration for Children and Families' Office of Planning, Research, and Evaluation. This secondary data analysis supports other project activities, including a review of the knowledge base, case studies, instrument development, and other secondary data analyses. The HS2K research team analyzed 23 MOUs from 10 Head Start programs that participated in the Office of Head Start & Public Schools Collaboration Demonstration Project (CDP). This 2020 initiative brought together many early childhood partners and staff across Head Start and public-school systems to improve collaboration and coordination on kindergarten transitions. These MOUs, a federal legislative requirement for both Head Start and Title I funded public-school systems, are written expressions of these partnerships that can shed light on the perspectives, policies, professional supports, and practices that influence kindergarten transition experiences. (1) Although kindergarten transitions were not the explicit primary focus of the MOUs, these documents often included detailed descriptions of partnerships across two systems that attempted to align expectations, resource allocations, and key activities; (2) When MOUs explicitly mentioned kindergarten transitions, there were three federal policy requirements often noted: (1) creating cross-system communication channels; (2) developing family collaboration and involvement practices; and (3) transferring, sharing, and obtaining student records and data; (3) Findings suggest that relatively few MOUs currently contain explicit references to kindergarten transition perspectives, policies, professional supports, or practices. Yet, MOUs remain an important potential vehicle by which to align transition-related activities with key legislation, statutes, and requirements, and create collaboration and communication structures. This brief provides examples of MOU language that may support aligned transition activities; and (4) There is an opportunity for HS programs and LEA administrators to think more collectively about and articulate joint policies, perspectives, practices and professional supports that support the kindergarten transition. However, there is also an opportunity for more specific federal and state guidance to programs and schools on what should be included in MOUs. [This report was prepared with the National P-3 Center.]