This essay delves into the profound and lasting impact of European colonialism on the global political economy. The introduction establishes the need for an eclectic approach to understand the contemporary global political economy, arguing that European colonialism is the single largest driving force behind its current state. The essay explores the rise of early colonial powers like Portugal, Spain, Holland, France, and Great Britain, driven by mercantilism, and examines the transatlantic slave trade and the British colonization of India as key examples of colonial exploitation. The essay then analyzes these historical events through the lenses of three major global political economy theoretical frameworks: economic nationalism, liberalism, and Marxism. Economic nationalism, rooted in mercantilism, is shown to have influenced the imperialistic actions of the European colonial powers, while liberalism is presented as a counter-ideology that eventually led to the decline of colonial empires. Marxism provides a critical perspective, arguing that colonialism and liberalism are simply different forms of capitalist exploitation. The essay concludes by emphasizing the importance of understanding European colonialism to better grasp the key developments in the global political economy and the historical context of the three mainstream schools of thought.