A successful outcome of the 2010 Nuclear Non-Proliferation Treaty (NPT) Review Conference is widely seen as vital if the NPT is to continue to play an important role in preventing nuclear proliferation. Focusing on the concept of trust, this article offers a novel perspective on the treaty and its future prospects. Too often dismissed as impossible or dangerous in international politics, trust has received little attention from both academics and practitioners. This article challenges this predominant view by making a case that the NPT establishes and embodies a series of trusting relationships between states. Trusting relationships are analysed as a way in which states relate to each other, taking into account both interests as well as promises. It does not make the case that once such relationships are established they will remain constant, but rather that trusting relationships are dynamic. They can be strengthened or weakened depending on the choices of actors. The article shows how trusting relationships have underpinned the NPT from its beginning and charts their evolution by reference to three key sets of relationships. These are, first, the relationships between the recognized nuclear weapon powers and the non-nuclear weapon states; second, those among the recognized nuclear weapon states; and third, those between the NPT signatories and those states remaining outside of the treaty. For each set of relationships the problems and issues that have eroded trust are outlined and the steps that might lead to the overcoming of these strains and the strengthening of the trusting relationships are discussed. By understanding the NPT through the prism of trust, the article sheds new light on both the achievements of the treaty as well as its potential fragility. At the same time, such an analysis opens up the directions of policy crucial to strengthening the treaty at the Review Conference and beyond.