The aims of the current paper are to contribute to theorizing in the field of collective action and also to bring this body of research closer with the literature on climate change. We suggest integrating the concept of social norms into the social identity model of collective action, to investigate the determinants of individuals' collective climate action intention. We argue that perceived social norms will be helpful in understanding the social identity-collective action link. Consistent with the proposed model, participants' (N = 538) intention to take part in a neighborhood-based climate protection initiative was predicted via all of the model constructs (social identity, perceived collective efficacy, and group-based emotions) but most strongly so by the perceived participation norm, which also fully mediated the effect of social identity on participation intention. Further analyses suggested that the emotional motivation to engage in collective climate action was based on group-based guilty conscience rather than anger. Discussion focuses on the importance of social context in understanding and combating climatic change, the emotionally flexible motivations behind different forms of collective action, and the role of group identification in interventions aimed at promoting pro-environmental behavior. Copyright © 2014 John Wiley & Sons, Ltd.