Procedural law, adjective law, in some jurisdictions referred to as remedial law, or rules of court, comprises the rules by which a court hears and determines what happens in civil, lawsuit, criminal or administrative proceedings. The rules are designed to ensure a fair and consistent application of due process (in the U.S.) or fundamental justice (in other common law countries) to all cases that come before a court.

Substantive law, which refers to the actual claim and defense whose validity is tested through the procedures of procedural law, is different from procedural law.

In the context of procedural law, procedural rights may also refer not exhaustively to rights to information, access to justice, and right to counsel, rights to public participation, right to confront accusers as well as the basic presumption of innocence (meaning the prosecution regularly must meet the burden of proof, though different jurisdictions have various exceptions), with those rights encompassing general civil and political rights. In environmental law, these procedural rights have been reflected within the UNECE Convention on "Access to Information, Public Participation in Decision-making and Access to Justice in Environmental Matters" known as the Aarhus Convention (1998).