The difficult question that provides the title of this essay is answered firstly by the Oxford English Dictionary – though not all that helpfully, given that its explanation is in need of explanation. Part of the problem is that the word ‘Romantic’ did not mean to the Romantics themselves what it now means to us (whatever that may be). True, German philosophers used it – though only in a highly specialized manner, as part of a binary opposition to the concept of Classicism. This essay goes on to take five poets of the period and attempts to suggest ways in which their thought comprises a unified, connected body of thought to which we can attach the label ‘Romantic’.