Lacanian theory offers a series of promising conceptualization – amongst then the notion of the ‘big Other’– which, despite their obvious analytical value, have been curiously neglected by critical social psychology. This paper concerns itself with an overview of this concept of the ‘big Other’ particularly in reference to how it may benefit critical social psychological analyses. The explanatory value of this notion is introduced via a series of Lacanian paradoxes (the Other as vanishing-point of inter-subjectivity that cannot itself be subjectivized; the Other as simultaneously ‘inside’ and ‘outside’; the Other as both embodiment of the social substance and yet also the site of the unconscious). I then move on to show how this notion opens conceptual opportunities for social psychological conceptualizations of the formation of the social. I close by demonstrating what the ‘big Other’ offers critical social psychological analyses of power.