In 1841, the twenty-eight-year old Søren Kierkegaard defended his master’s thesis On the Concept of Irony with Continual Reference to Socrates at the University of Copenhagen. This first major work by the young Danish philosopher gains particular attention in the second half of the twentieth - beginning of the twenty-first century, as irony becomes an important concept for poststructuralist theories of indeterminacy of language, as well as “the central mode of consciousness of postmodernism ”. Building on the existing parallels between romanticism and postmodernism, the present paper argues that On the Concept of Irony constitutes an implicit critique of postmodern irony in as much as it is explicitly critical of German Romanticism and Romantic irony. It presents a thorough reading of Kierkegaard’s criticism of Romantic irony and discusses how Kierkegaard’s idea of the “truth of irony” relates to the notion of irony in the postmodern condition.