In this project we investigate social media firestorm phenomenon. To advance the knowledge in social media firestorm research, we build upon the heuristic-systematic information processing model as the overarching framework to develop a research model that explains users’ information processing behaviors in social media firestorms. We further contextualize our research model based on the literature on moral psychology, social impact, and firm transgression. . Our empirical results showed that social media users adopted both heuristic and systematic information processing routes in arriving at their judgment of moral wrongness committed by the firm; however, the systematic processing route was biased by the heuristic cue presented in the social media platform. Besides, social media users exhibited varying degrees of retaliatory and avoidance behaviors against firms in the above firestorms.