This chapter examines public interest litigation (PIL) and its place in Indian constitutional law. The chapter begins with an overview of PIL as an instrument for dealing with public grievances such as flagrant human rights violations by the State, or for vindicating the public policies embodied in statutes or constitutional provisions. It then discusses the evolution of PIL in India and four distinct factors that contributed to its growth. It also explores how courts efficiently deploy judicial resources and decide genuine disputes of a legal character by recognising only those persons with locus standi, or legal standing. Finally, it describes a range of procedural innovations that distinguish PIL from conventional litigation and explains how the growth of PIL affected traditional notions of justiciability. It shows how the phenomenon of PIL has shaped both the nature of rights-based claims within Indian constitutional law as well as the role of the Supreme Court within Indian democracy.