The basic structure doctrine is an Indian judicial principle that the Constitution of India has certain basic features that cannot be altered or destroyed through amendments by the parliament. Key among these "basic features", are the fundamental rights granted to individuals by the constitution. The doctrine thus forms the basis of a limited power of the Supreme Court to review and strike down constitutional amendments enacted by the Parliament which conflict with or seek to alter this "basic structure" of the Constitution. The basic structure doctrine applies only to constitutional amendments. The basic features of the Constitution have not been explicitly defined by the Judiciary, and the claim of any particular feature of the Constitution to be a "basic" feature is determined by the Court in each case that comes before it. The basic structure doctrine does not apply to ordinary Acts of Parliament, which must itself be in conformity with the Constitution.

The Supreme Court's initial position on constitutional amendments was that no part of the Constitution was unamendable and that the Parliament might, by passing a Constitution Amendment Act in compliance with the requirements of article 368, amend any provision of the Constitution, including the Fundamental Rights and article 368. The "basic features" principle was first expounded in 1964, by Justice J.R. Mudholkar in his dissent, in the case of Sajjan Singh v. State of Rajasthan. He wrote, "It is also a matter for consideration whether making a change in a basic feature of the Constitution can be regarded merely as an amendment or would it be, in effect, rewriting a part of the Constitution; and if the latter, would it be within the purview of Article 368?"