The clear thrust of Percy Bysshe Shelley's radical politics has generally been considered as stopping short of questioning Britain's imperial policies, and the poet has frequently been accused of latent, if not overt, imperialism. This paper on Shelley and imperialism attempts to 'clarify' Shelley's thoughts in the context of British imperialism. Shelley, as a second generation Romantic poet, was witness to the birth of Britain's imperialism, and although he did not live long enough to experience the heyday of the British Empire, his time was a period of transition. The philosophy of the Enlightenment had begun its gradual transformation into the rhetoric of imperialism, and as Europe moved into the nineteenth century, the cosmopolitanism of the philosophers was eroding into nationalism. Thus, if Britain's great imperialistic project was still in the future in Shelley's time, the forces that were to underpin it were very much in the air-that curious blend of orientalism, evangelism, utilitarianism and nationalism. Yet the question remains as to whether he subscribed to these movements. It has been argued that he did. In this paper I suggest that, on the contrary, Shelley’s radical refutation of tyranny in every form and his commitment to humanity are transparently visible in every line he wrote. I propose to begin with an analysis of ‘The Assassins’ (1814), then to look at A Philosophical View of Reform, and to conclude with Shelley’s deconstruction of imperialism in Prometheus Unbound.