Both marketing researchers and practitioners have already recognized the great potential of emotions in different consumer behavior contexts, such as advertising and service interactions. Despite the high relevance of emotions in consumer behavior and marketing research, the concept of emotional contagion (that is, a receivers catching and mimicking of a senders emotions), is still a neglected area of research. This lack of empirical evidence on emotional contagion is related to the conceptualization and operationalization. This dissertation considers six thematically related empirical studies and first focuses on the general role of emotions in consumer behavior. Second, this dissertation examines the occurrence and relevance of emotional contagion in this context. Third, it investigates the impact of both emotions and emotional contagion on customer responses such as satisfaction. Four studies are thereby placed in a service context, while two studies focus on emotion displays integrated into ads. By applying the “Emotional Facial Action Coding Systems“ (EmFACS) instead of commonly used emotion measures, the author addresses a major gap in empirical emotional contagion studies in consumer behavior research. Thus, this dissertation contributes to emotional contagion theory by suggesting an innovative conceptualization and operationalization of emotional contagion that overcomes the weaknesses of previous studies in this field. Moreover, this dissertation contributes to consumer behavior literature by considering the relevance of the service environment for the impact of emotions on customer responses. Based on the empirical results, this dissertation provides marketers with practical implications which allows for a better understanding of the role of emotional contagion in the context of both service interactions and advertising.