This research examines the emergence of terrorism as a legal and political category in late colonial India from 1897 to 1946. Chapter 1 traces debates surrounding laws of sedition from the 19th century and follows these laws into the early twentieth century, where they come to be viewed as increasingly inadequate in dealing with the unprecedented challenge presented to the colonial regime by secret societies using bomb assassinations against the government. Chapter 2 then examines how these discussions change in the context of the First World War, when a language of war and concerns regarding third party German involvement provide the opportunity for the imperial government to strengthen its emergency laws by legislating against 'conspiracy'. Chapter 3 demonstrates how, following the end of the war, conspiracy became itself viewed as an inadequate term and officials made a conscious decision to present revolutionaries under the label of 'terrorism' in subsequent speeches. This continued into the early 1930s, where laws in India began to target terrorism as a discrete category of crime, in legislation such as the Suppression of Terrorism Outrages Act of 1932. Chapter 4 situates this process within the context of the international system of the interwar period, first exploring India's under-studied relationship with the League of Nations and then indicating how this relationship became a point of critique for those labelled by the government as terrorists, particularly the Bengali revolutionary Rash Behari Bose. Chapter 5 shows how the discussions surrounding the Convention for the Prevention and Punishment of Terrorism in 1937, the world's first international law to target terrorism as a discrete category of crime, reflected many of the concerns that animated discussions in India. The chapter also examines India's role in the Convention, as the only member-state of the League to ultimately ratify the treaty.