Keshavananda Bharti v. State of Kerala (1973) is a landmark case in the history of Indian constitutional law that established the basic structure doctrine. The case was heard by a 13-judge bench of the Supreme Court of India and dealt with the question of whether the Parliament of India had the power to amend the Constitution of India in any manner, or if there were certain fundamental principles that could not be amended.

The case arose after the Kerala government passed the Kerala Land Reforms (Amendment) Act, 1969, which aimed to redistribute land from large landowners to the landless. Keshavananda Bharti, a large landowner, challenged the Act, arguing that it violated his fundamental rights under the Indian Constitution.