The goal of this paper is to examine the characteristics of Indonesia’s middle power diplomacy and then to illuminate the domestic factors behind it. Middle power diplomacy of Indonesia started out with ‘independent, active’ foreign policy principles that emerged from the history of nationalism and anti-colonial revolution. Indonesian diplomacy has been characteristically that of middle-power with its interests in global issues, its preference for multilateralism, efforts to mediate in international conflicts, and norm diplomacy. Indonesian middle power diplomacy challenges the world order rather than carving out a niche, and pursues inclusive multilateralism that embraces as many countries as it can. Indonesia self-proclaimed as a leader of the developing world and imagined a new world order beyond the cold war politics of the great powers already in the mid-1950s, at a time it lacked diplomatic resources. In other words, Indonesia’s middle power diplomacy came out of its ‘great power consciousness’ that the country must lead the world with or without capacities to do so, rather than the country’s identity as a middle power.