For the last five years, Sweden has seen a quite remarkable milk war between the traditional Arla serving dairy products and the innovative Oatly offering vegan milk substitutes. The purpose of this thesis was to investigate how consumers’ attitudes are affected by firms’ involvement in brand rivalry, where the conflict between Arla and Oatly served as a case. A conceptual model based on previous research was created to shed light on essential elements that affect consumers’ attitudes. Empirical data was collected through a qualitative content analysis as well as two focus group interviews. Findings resulted in three main insights concerning consumers’ attitudes. Firstly, consumers’ attitudes depend on how the brands decide to leverage and influence consumers’ emotions, where humorous content can smooth over smear campaigns. Secondly, consumers’ attitudes are influenced by their degree of knowledge regarding the conflict, where knowledgeable consumers are often more critical to the content communicated in advertisements. Lastly, consumers’ attitudes are negatively affected if a brand’s core values do not cohere with its engagement in rivalry. This dissertation has contributed to additional insights into brand rivalry initiatives from a consumer perspective. Brands should consider a public conflict more carefully to avoid negative attitudes among consumers.