Employee non-compliance with information systems (IS) security procedures is a key concern for organizations. However, even though the importance of having effective IS security training is widely acknowledged by scholars and practitioners, the existing literature does not offer an understanding of the elementary characteristics of IS security training, nor does it explain how these elementary characteristics shape IS security training principles in practice. To this end, this thesis develops a theory that suggests that IS security training has certain elementary characteristics that separate it from other forms of training, and sets a fundamental direction for IS security training practices. Second, the theory defines four pedagogical requirements for designing IS security training approaches. Then it points out that no existing IS security training approaches meet all these requirements. To address these shortcomings, the way in which to design an IS security training approach that meets all these requirements is demonstrated. In this thesis it is also argued that, along with an effective IS security training approach, reasons for employees’ IS security behavior need to be understood. The existing empirical research in the field of employees’ IS security behavior is dominated by theory-verification studies that test wellknown theories developed in other fields in the context of IS security. Instead, it is argued that there is a need to focus the investigation on the phenomenon of employees’ compliance itself through an inductive and qualitative approach to complement the existing body of knowledge of this topic. As a result, a framework identifying reasons associated with compliance/noncompliance with security procedures is developed. A particularly interesting finding is that individuals’ violation of IS security procedures depends on the type of violation. Besides advancing a meta-theory for IS security training and developing the theoretical framework that points out reasons for employees’ IS security behavior, the thesis provides a future research agenda for IS security training and behavior. For practitioners, this thesis points out the limitations of the previous IS security training approaches and reasons for IS security behavior and, based on these observations, offers principles for designing effective IS security training approaches in practice.