Corporate social and environmental disclosure, later redefined as sustainability disclosure in order to include the third pillar of sustainability (economic), has been the subject or significant research over the past four decades. A major branch of empirical research has specifically focussed on the determinants of disclosure; those factors which correspond with greater breadth and depth of disclosure. Research has traditionally been focussed on the developed world, specifically North America and Western Europe and either addressed social or environmental disclosure in isolation or various hybrids of the two.This research has two aims. Firstly it is an attempt to provide a view of disclosure in Africa, and specifically South Africa, where only minor empirical research has been undertaken. Secondly and crucially, this research attempts to address shortcomings in the existing body of research in that factors have traditionally been analysed for significance with regards to individual sustainability pillars alone, or at the aggregate level. A content analysis technique was employed to score sustainability reports for social, environmental and economic disclosures. An analytical model was then developed and a number of internal and external factors analysed to establish which were significant determinants of the level or extend of disclosure at both the individual pillar level and then compared to the aggregate or overall disclosure.