Abstract: Kongsfjorden, a fjord in north-western Svalbard, is characterized by large environmental gradients driven by meltwater processes along the margins of tidewater glaciers and the inflow of relatively warm Atlantic Water, the main heat source for the European Arctic. These factors make Kongsfjorden a key area to investigate changes in the polar climate–ocean–glacier system and to examine the resulting effects on the marine environment. The aim of this paper is to synthesize knowledge about the marine sedimentary environment in Kongsfjorden since the last deglaciation. Fjords act as natural sedimentary traps, archiving information about past and present environmental conditions and changes. Geological studies of Kongsfjorden have demonstrated a good potential for reconstructing palaeoenvironments and establishing baselines values for the natural climate changes in the Arctic. Palaeoceanographic reconstructions reveal rising water temperatures similar to modern temperatures ca. 12 000 years ago. The extent of warm Atlantic Water entering the fjords influences processes at, and the stability of, the margins of the tidewater glaciers. Enhanced inflow may cause accelerated glacial melting that, in consequence, leads to an increase in the sediment flux from the glacial catchments into the fjord, as observed ca. 12 000 years ago and at present. However, responses of sediment flux to modern environmental changes remain poorly understood, hence long-term and monitoring studies are needed to quantify and model the effects of climate warming on the sedimentary environment of Kongsfjorden.