The paper Hamann and Herder on Metacriticism. A Contribution to the History of Concepts deals with a general context of the origin and extension of the neologism “metacriticism”. The history of this term begins in 1784 when German writer and philosopher J. G. Hamann used it to name his conception of Immanuel Kant’s Critic of Pure Reason. However, Hamann provided only a brief framework of the conception of metacriticism. The task to elaborate the whole theory was undertaken by J. G. Herder, who published two-volume work Verstand und Erfahrung. Eine Metakritik zur Kritik der reinen Vernunft in 1799. Here begun a long-term conflict in German philosophy about the conception of metacriticism, about Herder’s controversial criticism of Kant and generally about the task of critical philosophy. Modern research shows that there are series of impulses in Hamann’s and Herder’s theory of metacriticism which influenced the development of German idealism philosophy. Attached to this paper is the translation of Hamann’s very first text in which the term metacriticism occurred.