The Monroe Doctrine was originally formulated as a US foreign policy principle, but in the late nineteenth and early twentieth centuries it began to be redefined in relation to both the hemispheric policy of Pan-Americanism and the interventionist policies of the US in Central America and the Caribbean. Although historians and social scientists have devoted a great deal of attention to Latin American anti-imperialist ideologies, there was a distinct legal tradition within the broader Latin American anti-imperialist traditions especially concerned with the nature and application of the Monroe Doctrine, which has been overlooked by international law scholars and the scholarship focusing on Latin America. In recent years, a new revisionist body of research has emerged exploring the complicity between the history of modern international law and imperialism, as well as Third World perspectives on international law, but this scholarship has begun only recently to explore legal anti-imperialist contributions and their legacy. The purpose of this article is to trace the rise of this Latin American anti-imperialist legal tradition, assessing its legal critique of the Monroe Doctrine and its implications for current debates about US exceptionalism and elastic behaviour in international law and organizations, especially since 2001.