As the post-colonial Global South was weaving together the Third World Movement in the 1950s, it was also struggling to arrive at a common definition of colonialism. Since the movement was primarily premised on anti-colonial sentiments, redefining the term ‘colonialism’ could change its parameters. This article examines debates between three Asian leaders – Jawaharlal Nehru, Sukarno, and Sir John Kotelawala – who proposed three different meanings of colonialism. These definitions were informed by distinct ways that the colonial experience was remembered in their respective countries. Each definition was meant to redirect the energies of the Third World Movement towards a different vision of a post-colonial global order. The three leaders debated this question in major Afro-Asian conferences of the mid-twentieth century. Their disagreements represented a foundational fissure in the movement. Relying on primary sources from multiple countries, this article recovers a political dialogue within the Global South unmediated by the West, which is often ignored by the scholarship.