The Amundsen Sea Low (ASL) is a distinctive feature of the Southern Hemisphere (SH) high latitude atmospheric circulation, regulating regional Antarctic climate, meridional heat transport, ocean circulation, and sea-ice in the Amundsen-Bellingshausen Seas. Most previous research on the ASL has focused on its variability with only a few studies attempting to understand why the climatological ASL exists. These studies have proposed different hypotheses to explain the presence of ASL, however, a clear understanding of the mechanisms responsible for the generation of the ASL remains uncertain. Here we use an atmospheric general circulation model to show that the ASL is a consequence of the interaction between Antarctic topography and the westerly wind jet, with negligible influence from low-latitude teleconnections. A non-rotating fluid flow simulation further suggests that the ASL can be explained by flow separation resulting from the interaction of westerly winds with the topography of Antarctica.