Recently, it seems as if the general opinion about marketing has deteriorated, in particular due to broadly discussed scandals. At the same time, there has been increased interest in corporate social responsibility and ethical conduct. Hence, this paper evaluates marketing activities with the help of an ethical theory as a normative basis, namely the Theory of Justice by John Rawls. The author, Julia Naskrent, first gives an introduction to the basic concepts of ethics and marketing. After justifying its use for the purpose of this paper, the Theory of Justice is operationalized in order to make it applicable for the actual analysis of marketing activities which is made in accordance with the marketing mix. At the end of the first part of the paper, a model of the most important findings is presented and forms the basis for the second part. Here, ways to legitimize marketing activities are presented by demonstrating several instruments and initiatives companies can establish. Due to combining ethical theory and philosophy with practical marketing activities, this paper is interesting for practitioners such as marketers, as well as philosophers, scholars and economists.