This article seeks to explain South Africa's ostensible emergence as a middle power. It makes the case for the use of a Coxian-based critical theory perspective, which relates the interrelationship between change at the level of world order, the nature of production and the social forces operative in the middle power's state-societal complex to explain South Africa's increasingly active role in international affairs. Playing a mediatory role helps the South African state make diverse foreign policy goals more compatible and it also goes some way in thwarting criticism levelled at its foreign policy in the state-societal domain. Contrary to earlier theorising about middle powers, this article supports a more recent contention that middle powers act in their own (ie dominant societal) interests. The value of such a perspective is illustrated in the light of current debates about the apparent incongruity of South African foreign policy.