This thesis consists of an in-depth literature review, that serves as a basis of the creation of a theoretical framework of Forgiveness in customer relations. In a first step, the construct of Forgiveness is conceptualized. From the conceptualization the following results are derived: Forgiveness is not an event or an outcome, but a lengthy process that goes through several phases. In this area, the literature is largely consistent, however, the process is presented in different ways. The most common process models have been combined into a new one, that considers the sequential phases found on intra- and interpersonal level and includes emotional, cognitive and behavioral elements. Based on insights gained from mostly psychological literature, a working definition is created. The presented theoretical framework sets the construct of Forgiveness in a context with customer relations to gain a better understanding of the negative effects of Forgiveness in these relations. The framework is divided into four sections: Transgression, Forgiveness-Process, Moderators and Effects. In the literature there is no evidence that the Forgiveness Process is related to negative effects in any way. On the other hand, a few negative effects caused by the expression (or communication) of Forgiveness are observed by studies from various scientific disciplines. According to those studies the expression of Forgiveness can lead to an imbalance in the relationship, which triggers a sense of guilt in the transgressor and consequently perceived stress. In addition, the expression of forgiveness can lead to a repetition of transgression. The third effect relates to an act of forgiveness associated with weakness, which may results in loss of trust in the relationship. This theses backs those findings on a theoretically level and postulates several propositions that lead the way for the second part of the thesis, a qualitative investigation of forgiveness.