This chapter explains the significance of statutory interpretation and how problems of interpretation arise. The chapter considers in detail the courts’ approach to interpretation, and traditional rules such as the literal rule, the golden rule, and the mischief rule are all analysed with examples from the case law. In modern times the courts employ a more purposive approach to interpretation, and there is coverage of how this approach works in practice. In particular, the chapter outlines a range of intrinsic and extrinsic aids to interpretation that the courts can rely on in interpreting an Act of Parliament. Among others, these aids include the long title, cross-headings, marginal or side notes, dictionaries, pre-parliamentary materials, statutes on the same subject matter, and, most notably, Hansard. The chapter concludes with an overview of the rules of language, namely ejusdem generis, noscitur a sociis, and expressio unius est exclusio alterius.