Legal aid is the provision of assistance to people otherwise unable to afford legal representation and access to the court system. Legal aid is regarded as central in providing access to justice by ensuring equality before the law, the right to counsel and the right to a fair trial. This article describes the development of legal aid and its principles, primarily as known in Europe, the Commonwealth of Nations and the United States.

A number of delivery models for legal aid have emerged, including duty lawyers, community legal clinics and the payment of lawyers to deal with cases for individuals who are entitled to legal aid.

Legal aid is essential to guaranteeing equal access to justice for all, as provided for by Article 6.3 of the European Convention on Human Rights regarding criminal law cases. Especially for citizens who do not have sufficient financial means, the provision of legal aid to clients by governments will increase the likelihood, within court proceedings, of being assisted by legal professionals for free (or at a lower cost) or of receiving financial aid.