Social commerce is an important issue and a new area to explore in today's business world. To be successful at social commerce requires a strong brand engagement on the side of the consumers and well-crafted brand marketing strategies on social media channels. Here in this study, S-O-R model is utilized to come up with a model explaining how social commerce stimuli affect consumers' cognition, affection and activation (engagement) with brands, and thereafter lead to brand trust and purchase intention on social media. The social commerce stimuli includes sales campaigns, personalization, interactivity, consumer generated content and reviews. If tested, the results of the study are believed to guide brand managers and social commerce managers in creating right marketing stimuli for success in social commerce. Additionally, the results of the study are believed to add to the newly forming literature on social commerce, online brand engagement, relationship marketing, and online purchase intention. (C) 2015 The Authors. Published by Elsevier Ltd.