The 'Movius Line' is the putative technological demarcation line mapping the easternmost geographical distribution of Acheulean bifacial tools. It is traditionally argued by proponents of the Movius Line that 'true' Acheulean bi faces, especially hand axes, are only found in abundance in Africa and western Eurasia, whereas in eastern Asia, in front of the 'line', these implements are rare or absent altogether. Here we argue, however, that the Movius Line relies on classifying undated surface bi faces as Acheulean on typological grounds alone, a long-standing and widely accepted practice in Africa and western Eurasia, but one that is not seen as legitimate in eastern Asian contexts. A review of the literature shows that bifaces are relatively common as surface finds in Southeast Asia and on this basis we argue that the Movius Line is in need of reassessment.