The article offers a critical study of the concept of “secular martyrdom”, sporadically used today in academic research, philosophy, and journalism. Its purpose is (1) to understand what it means in the current usage and (2) whether or to what extent it is legitimate (3) to propose an original judgment on the existence, boundaries, and scope of this phenomenon. Concerning the first issue, the author scrutinizes the concept of a martyr’s “cause” (for which he or she allegedly suffered and died), observes its Christian theological roots, and proves that the identification of a certain “cause” and its subsequent labeling as “secular” is not an etic, but an emic position, which undermines the credibility of the research. To answer the second of these questions, the author proposes to distinguish two components in each case of martyrdom: its cause as understood “from within”, from the position of a martyr and their venerators, and its arrangement, the language of martyrdom. On the basis of an analysis of four cases labeled as “secular martyrdom” - E. Davison, J.-P. Marat, A. Lincoln, J. Brown - the author concludes that their religious component is too strong to consider their martyrdom secular. Finally, the author considers the ideology of revolutionaries in 19th century Russia and 20th century USSR and China, as supposed examples of “real” secular martyrdoms. He concludes that the secularization of martyrdom is achieved through the abolishment of the religious arrangement given a conditionally secular cause.