The heritage of the architectural Avant-garde in Ukraine, formed in the interwar period (1921-1939), is large-scale in the number of objects and diverse in their typology, techniques and forms of expression of modern architectural ideas. Volyn – a historical Ukraine region that, at that time, was part of Poland (the Second Polish Republic) – plays a special role in this context. To date, the region has preserved a significant array of objects that demonstrate the specifics of the interpretation of European and Polish Avant-garde concepts. The article attempts to analyze the architectural context, ways of spreading and formation features of the architectural image of residential and public buildings as part of the European heritage of Interwar Modernism. Lack of professional evaluation and recognition of the objects’ value leads to their gradual degradation, reconstruction or destruction. Methods of comparative and stylistic analysis, archival research and field surveys of architectural objects were used in this research. The study showed that the spread of the Avant-Garde style in the architecture of Volyn was significantly delayed compared to similar processes in the architecture of Western Europe and Poland and reached its peak at the end of the interwar period. The use of formative techniques of Avant-Garde architecture in housing construction became an identifier and symbol of the social prestige of certain social groups. The design of public buildings reflected Volyn’s rapid social modernization.