This article explores the antagonism between Sigmund Freud and the German neurologist and sexologist Albert Moll. When Moll, in 1908, published a book about the sexuality of children, Freud, without any grounds, accused him of plagiarism. In fact, Moll had reason to suspect Freud of plagiarism since there are many parallels between Freud’s Drei Abhandlungen zur Sexualtheorie and Moll’s Untersuchungen über die Libido sexualis. Freud had read this book carefully, but hardly paid tribute to Moll’s innovative thinking about sexuality. A comparison between the two works casts doubt on Freud’s claim that his work was a revolutionary breakthrough. Freud’s course of action raises questions about his integrity. The article also critically addresses earlier evaluations of the clash.