Sales promotions, although ill defined and under theorised, have long been a part of the marketing communications mix and used by brands in a variety of ways in many different contexts. Much of the research that examines sales promotions has done so from a rational economic or behaviourist perspective. Whilst acknowledging the contribution of such ontologies, it is argued that there has been limited examination of sales promotions from a managerial perspective. What has been produced tends to be largely prescriptive and written for practitioners. In this thesis the ontology of critical realism has been used to develop a conceptual framework that treats sales promotions as individual entities taking place within organisational and market structures. This conceptual framework has been used to analyse empirical data collected from thirteen smaller U. K. brands drawn from a diverse set of product categories and industries. Four in-depth case studies are presented with rich, fine-grained insights into the behaviours of those involved in such activities and the subsequent outcomes; in particular the contemporary practices of managerial actors involved in the conception, commissioning and implementation of sales promotions activities. The results of a further 9 case studies are also presented in summary form. In each case the conceptual framework proves largely effective in interpreting the likely causes of the form that the sales promotion took and its subsequent outcomes. It is claimed that the research made the following contributions to the study of sales promotions: I) a re-examination of the definitional discourse that informs sales promotion and the development of a new definition ; 2) the early and successful use of the combination of a critical realist ontology and case study 3) that the forms and outcomes of sales promotions can be better understood as being dependent on causal explanations of involving organisational and business contexts and 4) the development of a model that integrates diverse contextual factors from both within and outside of the organisation in order to inform the managerial practice of deploying and managing sales promotions. The products of the study argue for a deeper and more sophisticated treatment of the way that sales promotions are researched, operate and are managed. The findings also suggest that both the method and the results have wider implications for the study of sales promotions, marketing communications in general and marketing practice.