In Turkish legal history, international treaties have gone through various developmental stages, affected by the current political, economic, and social conditions. The treaty texts, which had different characteristics from one another during the Ottoman period, diverged from each other in terms of legal consequences during the collapse of the state. The Ottoman Empire did not neglect to closely follow the international developments regarding the innovations that emerged in the technical, cultural, and economic fields in the XIXth and XXth centuries. Therefore, in addition to the centuries-old capitulation regime, the Ottoman Empire also participated in the system of multilateral treaties created by modern international law. Following the period of the War of Independence, the Treaty of Lausanne, which constituted the basis of the newly established state in terms of international law, dealt with the subject of international treaties in all points of view, abolished capitulations completely, and introduced various regulations on international treaties that entered into force during the Ottoman period or whose negotiations were participated in. This context has placed the Treaty of Lausanne at the centre of succession and continuity debates. The provisions of the Treaty of Lausanne on international treaties that were ratified or only negotiated during the Ottoman period contributed to the international legal policy to be followed in the Republican era and constituted the first stage of realizing of the Great Leader Atatürk’s goal of modernisation through international treaties based on the principles of full independence, equality, and reciprocity in all fields.