Data sharing has become an enabler of a diverse and important set of activities in areas such as science, law enforcement, and commerce. Data sharing scenarios frequently involve issues such as personal confidentiality, data misinterpretation, the potential for malicious exploitation of shared data, data with proprietary or first-use value, secret data, and governmental regulation. For these reasons, the need to state and enforce data sharing policy has grown increasingly significant. In this talk, we discuss models for data sharing policy and their key concepts.