Brands are increasingly incorporating social causes into their campaigns to address significant matters. In this context, social media is seen as a pivotal platform, as it has been a driving force behind public engagement and action, and hence the broader recognition of societal issues. For brands that aim to make a change, it is therefore important to know what types of messages are most likely to evoke consumer engagement. Yet, less is known about which message characteristics spur consumer engagement of cause-related brand posts. The aim of this paper is to investigate two characteristics that seem to play central role: prominence and thematic alignment. Based on a content analysis of 1,236 social media messages (Instagram and Facebook), the results indicate that consumers engage more with cause-related brand posts when these posts are aligned with the brand’s purpose. Importantly, product prominence is not appreciated in this context. Implications are discussed.