The absence of legal and regulatory frameworks around the collection, sharing and use of agricultural data contributes to the range of challenges currently being faced by farmers considering adoption of smart farming technologies. Many laws potentially influence the ownership, control of and access to data, in this paper we examine the attitudes of farmers to the collection, control, sharing and use of their farm data. Australian agriculture and the attitudes of Australian farmers to the adoption and uptake of smart farming technologies is used to highlight the tensions., however the issues and challenges raised are common to many agricultural industries throughout the world. We combine insights from a survey of Australian farmers with a legal analysis of the way in which agricultural data are collected, controlled, shared and used. We argue that the lack of transparency and clarity around issues such as data ownership, portability, privacy, trust and liability in the commercial relationships governing smart farming are contributing to farmers’ reluctance to engage in the widespread sharing of their farm data that smart farming facilitates. At the heart of the concerns is the lack of trust between the farmers as data contributors, and those third parties who collect, aggregate and share their data. The aim of this paper is to examine the issues giving rise to this lack of trust. We conclude with recommendations on how to address these concerns and facilitate the improved adoption of smart farming technologies, focusing on the need for the social architecture of the agricultural data relationships to change. To achieve this change, open dialogue, education and awareness raising and good data governance are essential to help build trust in the adoption of smart farming systems.