This chapter looks at another way of acquiring an interest in land, through the doctrine of proprietary estoppel. It discusses the two-stage process of acquiring an interest in land through proprietary estoppel: establishing an equity and satisfying the equity. It explains the three main elements that need to be proved to establish the equity. These are assurance, reliance, and detriment, and it gives case law examples of where these have been considered. It considers the wide range of remedies that may be awarded at the court’s discretion. It then looks at some interesting recent developments in proprietary estoppel and addresses an overarching element of proprietary estoppel claims: unconscionability. Finally, it examines the differences between the constructive trust and proprietary estoppel.