While recent research on sustainability communication demonstrates the relevance of message framing, research on the effects of message framing on consumers’ emotions is scant. Using the Stimulus- Organism-Response (S-O-R) framework, this paper examines the impact of environmental advertisements (stimuli) on two discrete emotions – hope and guilt – (organism) and how these emotions influence consumers’ behavioral intentions (responses). Relying on the prospect theory, this study focuses on positive (gain) and negative (loss) frames. Study 1 shows that, in the context of Corporate Social Responsibility (CSR), a gain message elicits hope while a loss-message triggers guilt. Study 2 shows that both emotions positively influence consumers’ attitudes toward the cause; however, only hope affects attitude toward the company. Attitudes toward the cause and the company, in turn, influence consumers’ behavioral intentions.