Rapid change in the business environment due to economic, political, and technological factors forces organizations to adapt accordingly. Therefore, implementing agile working models can be beneficial for organizations aiming to develop an adjustable and competitive business model, which provides the ability to respond to changing market needs in a timely and effective manner. Furthermore, it enables organizations to achieve improvements in quality, flexibility, communication and collaboration, and employee as well as customer satisfaction. Originating in the field of software development, agile methodologies were designed for small, co-located, and self-organizing teams. However, successes in a small setting inclined organizations to likewise adopt these principles and methods at scale. Whilst adopting agile practices at scale, new challenges emerged, yet large organizations increasingly seek to implement agile working models due to their improved performance, flexibility and speed. Therefore, it is crucial for both, researchers and practitioners to understand factors putting such transformations at risk. Whilst there are several descriptions of challenges during large-scale agile transformations, research is yet to develop a comprehensive understanding of overarching stress situations that can occur during such transformations, endangering their progress. This thesis aims to contribute to the scientific conversation on large-scale agile transformations through developing a highly relevant construct by means of a multiple case study on stress situations, which can occur during large-scale agile transformations. This thesis uses a model of stress, known from research in natural sciences to interpret stress during such transformations. In this context, a stressor is an environmental event that distracts the process of a large-scale agile transformation away from the planned track. This situation can trigger a positive, as well as a negative perception, including combinations of both, depending on the individual or organization. Results of this thesis are twofold. First, this thesis examines reasons for companies to undergo such transformations. The second part of this thesis focuses on stress situations found in ongoing or finished large-scale agile transformation projects, as well as their origin, classification and impact. Results are presented in a comprehensive cluster scheme, which enables the analysis of different stress situations according to a common theme.