Although there is a broadly similar core of human rights law and courts in different jurisdictions face strikingly similar questions, the use of comparative law in the human rights context remains controversial. Reference to foreign human rights materials is regarded as undemocratic, selective and misleading. Rather than searching for a single ‘right answer’, or expecting convergence, this article addresses these challenges from a deliberative perspective. A deliberative approach requires decisions to be taken on the basis of reasons which are thorough and persuasive. Even where outcomes diverge, there need to be good reasons, whether textual, institutional, or cultural. Comparative materials constitute an important contribution to this process. Part I critically assesses various alternative potential functions of comparative law. Part II develops the deliberative model while Part III addresses the main critiques of comparative law. Part IV tests the deliberative approach against a selection of cases dealing with two particularly challenging issues confronted by courts in different jurisdictions, namely the use of substantive principles such as dignity, and the application of justification or limitation clauses in the context of prisoners' right to vote. Case law is drawn from countries which already cite each other and which have broadly similar institutional frameworks: the USA, Canada, South Africa, India, Australia, the UK, New Zealand and the European Court of Human Rights to the extent that it too considers comparative law.