This paper aims to present some aspects of the Late Pleistocene–Holocene lithic industry in the inland East Kalimantan region by studying the assemblages found in three rock shelter sites in the karstic area of the Mangkalihat peninsula. This study analyzes these assemblages in their regional techno-complex taking into consideration the environmental components. It focuses on certain aspects of stone flaking technology and the trends in the reduction sequences of the assemblages. Our results shows that the reduction sequences, flaking technology and the typology of the blanks and tools, persisted across the Pleistocene/Holocene boundary, as revealed in Liang Abu where the lithic artifacts were found throughout the stratigraphic sequence (over at least 20,000 years). Other excavations in Liang Jon and Liang Pemalawan have confirmed this continuity until the historical eras. In addition, this research emphasizes the potential influence of the environmental and climatic stability (persistence of the rain forest) during at least the last 40,000 years in this region, as well as the inland geographical location, on the continuity of the local stone flaking technology.