This PhD is about “remedies” in “constitutional review.” Constitutional review is where litigants bring a case to the superior courts (i.e., the High Court, Court of Appeal or Supreme Court) challenging the constitutionality of some exercise of state power – generally legislation. Think, for example, of legal challenges to the constitutionality of legislation prohibiting public worship during pandemics, or of constitutional challenges to legislation criminalising assisted suicide. Remedies are the practical parts of a court’s judgment which concretise a litigant’s rights. From the litigant’s perspective, they are the most important part of a court’s judgment. After all, there would be little point in claiming constitutional rights without effective remedies for their violation. The most basic remedy is a declaration of invalidity, i.e., when courts invalidate laws because they infringe constitutional rights. In recent years, however, courts have become more innovative in the remedies they use. This thesis thus explores the nature and scope of the “remedial discretion” that judges ought to enjoy where they find legislation is inconsistent with the constitution. That is, it assesses whether judges ought to enjoy greater flexibility in respect of the practical solutions available to them in cases where they find a law is unconstitutional than has traditionally been the case in constitutional democracies. The thesis is concerned with describing, analysing, and comparing existing arrangements and practice in this area of constitutional law in selected jurisdictions around the world – namely Canada, Ireland, and the United Kingdom. And it aims to inform judicial practice, institutional design, and constitutional reform. It also draws on works of constitutional and political theory in developing a series of “remedial touchstones” which serve to both ground and constrain the remedial powers available to judges in constitutional review of legislation.