Grasslands of the Tibetan plateau are commonly believed to be degrading as a result of unsustainable grazing practices. In response, the Grassland Law attempts to allocate grasslands based on the Individual Household Responsibility System model that has worked in the agricultural areas of China. However, the actual tenure scenario in the rangelands of Tibet is not as open access as is commonly implied. Communal forms of pasture tenure and management (including village level and kin-group arrangements) are advantageous given the socio-economic and ecological context. This paper will review the inherent logic of opportunistic movement in these high altitude rangelands, the “rationale” for existing grassland policies, and the impacts of these policies in the Tibetan Plateau. It will then discuss models for policy implementation that allow flexibility in legal tenure contract and management arrangements that better reflect the de facto common property situation in these areas. These models reflect local interpretations of policy that promote more equitable resource rights within a common property regime rather than individual “usufruct” property rights as proposed in more strict interpretations of law.