The Constitution Bench is an institutional concept within the Supreme Court of India, not a permanent body, established to decide matters of profound constitutional significance. Its legal foundation is Article 145(3) of the Constitution of India, which mandates its formation. This provision was included to ensure that any case involving a "substantial question of law as to the interpretation of this Constitution" is decided by a sufficient quorum of judges. The first matter heard by a Constitution Bench was A. K. Gopalan v. State of Madras.
The mechanism requires a minimum of five Judges to sit for the purpose of deciding such a case or for hearing any reference made by the President of India under Article 143. The Chief Justice of India (CJI), as the master of the roster, holds the power to constitute the bench and refer cases to it. Unlike a regular Division Bench (two or three judges), a Constitution Bench is typically temporary and is dissolved once the specific legal question is resolved.
The concept is intrinsically connected to landmark judgments that have shaped Indian polity, such as Kesavananda Bharati v. State of Kerala (1973), where a 13-judge bench—the largest ever—propounded the Basic Structure Doctrine. This doctrine holds that Parliament's power to amend the Constitution is wide but not unlimited. A larger bench, such as a seven-judge bench, is required to review or overrule the pronouncement of a five-judge Constitution Bench. While the legal provision of Article 145(3) remains unchanged, the CJI has recently promised to strive for at least one Constitution Bench to function throughout the year, addressing the historical ad hoc nature of their sittings.