This thesis begins with theoretical approaches to fantastic literature. There are numerous theoreticians/authors working in the field of the fantastic, which has led to numerous definitions and attempts at systematization. Tzvetan Todorov was one of the first to author an all-encompassing study of the fantastic. Most theoreticians who came after Todorov either followed in his footsteps or opposed him, but certainly interacted with his study. One of the biggest points of contention in this field of theory is the differentiation of the fantastic according to categories of genre (as Todorov first posited), mode (a suprageneric category), property (thematic elements present in a work that are not necessarily prevalent in the genre) and impulse (the imaginative process in works either belonging to the fantastic or possessing some of its attributes). This is discussed further in the theoretical overview. The chapter on theory introduces some functions of the fantastic, as well as the dichotomy between the real and the fantastic. Although there are multiple dichotomies related to the fantastic, this one is singled out because the real or factual is most frequently used as a starting point when defining the fantastic. The second part of the thesis discusses the possible designations of the literary-historical period from the avant-garde to postmodernism. Multiple terms are used in reference to this period, such as late modernism or „druga moderna“. There is an affinity between the fantastic and modernism, arising from their common tendency to deviate from mimetic representation of reality. The chapter also includes analyses and interpretations of selected Croatian authors (Nikola Šop, Vjekoslav Kaleb, Vladan Desnica, Antun Šoljan, Krsto Špoljar and Ranko Marinković), as well as international writers (Franz Kafka and Karel Čapek). The final part of the thesis presents conclusions drawn from these analyses and interpretations. There is no uniform model of the fantastic in Croatian literature from the avant-garde to postmodernism but there are links between selected authors.