During the last three decades, information and communication technologies have fundamentally changed the way we work, live and communicate. The ubiquity of internet services, which become increasingly interactive and complex, together with enhanced connectivity, facilitated by innovative mobile devices, induces an ever-rising demand for computing, storage and data transmission capacities. Today, information systems (IS) constitute the backbone of the globalized economy and are indispensable for modern business and production processes. At the same time, environmental sustainability has evolved as the most pressing societal challenge of the 21st century, in particular due to the looming threats of climate change. By virtue of their global influence and reach, business companies significantly contribute to the creation of environmental problems, but owing to their organizational knowledge, capabilities and resources, they also have the capacity and ability to play a key role in shaping the path towards a more sustainable development. The companies leading the way have noticed that corporate sustainability is not necessarily a burden that negatively impacts their bottom line. If strategically managed, environmental product and process innovations can decrease operational costs, enhance corporate reputation, and differentiate from competitors. With regard to environmental sustainability, IS play a contradictory role: on the one hand, the manufacturing, operation and disposal of information technology (IT) infrastructure are responsible for serious environmental impacts: from the mining of conflict minerals to carbon dioxide emissions that equal those of the airline industry to enormous amounts of toxic e-waste. On the other hand, IS are perceived as key enablers of a "green" economy: environmental management systems and the reengineering of business processes can substantially reduce the environmental impacts of business organizations, while technological innovations provide opportunities to decrease the ecological footprint of end-user products and services. Many organizations have started to implement first environmental measures to decrease IT energy consumption and to reduce operational costs, mostly in an unstructured and uncoordinated manner though. Although Green IS practices feature a considerable potential to increase corporate environmentalism while creating promising business opportunities, the adoption of enterprise-wide cross-functional initiatives aimed at implementing Green IS has been rather slow. Economic uncertainties regarding the long-term effects of Green IS adoption and the lack of appropriate management frameworks have been identified as main inhibitors of an encompassing implementation of Green IS initiatives throughout the enterprise. In this context, this thesis addresses relevant research gaps, contributes to theory development in the evolving Green IS research discipline, develops practice-oriented management frameworks, and emphasizes the importance of following a strategic approach to leverage the competitive potential of Green IS. This cumulative thesis comprises an introduction that includes a literature review and a pre-study, four theory-based conceptual research articles, and two empirical studies, one of them building on qualitative, exploratory case study research whereas the other relies on quantitative data which has been analyzed with structural equation modeling. This thesis targets four specific research goals to advance theory-building in Green IS research and to promote the adoption of Green IS in practice. First, this thesis clarifies and defines the central terms and key concepts Green IT, Green IS, Green IS strategy, and Green IS practices drawing on a transdisciplinary research approach. Second, the most important challenges and inhibitors of Green IS adoption are identified and characterized. In particular, the lack of management frameworks, which encourage a holistic implementation that follows a strategic rationale, the complexity of strategic Green IS alignment, the multi-dimensional performance impacts of cross-functional initiatives and, above all, the uncertainty relating to the business case of Green IS practices, are identified as the most pressing challenges. Third, current actions of business firms to address these challenges are examined. Building on exploratory case study research, distinctive Green IS strategies are identified in managerial practice. Most notably, the empirical insights from quantitative survey research suggest a positive relationship between Green IS adoption and firm competitiveness, thus decreasing the economic uncertainty which inhibits the implementation of far-reaching environmental initiatives. Fourth, practice-oriented management frameworks are developed. The fine-grained Green IS strategy concept advises the formulation of strategies addressing the corporate, competitive, and functional management level. The proposed typology of four Green IS strategies illustrates distinct strategic options, from which executives can choose under consideration of their competitive targets and the firm-specific context. To allow for consistency of Green IS strategies, the presented alignment framework facilitates coherence with economic and environmental corporate goals. Furthermore, the actors, roles and responsibilities relevant to the alignment process are described. In addition, a management framework for the holistic adoption of Green IS, which specifies decisive management areas and distinguishes between three degrees of environmental impacts, is presented along with a comprehensive catalogue of Green IS implementation measures. As a consequence, this research offers both empirical insights and conceptual models to advance the adoption of Green IS initiatives, thus meeting the challenges of climate change and turning corporate sustainability into a business opportunity. Informationssysteme (IS) zeigen in Bezug auf ökologische Nachhaltigkeit gegensätzliche Eigenschaften. Einerseits verursachen die Herstellung, der Betrieb sowie die Entsorgung von Informationstechnologie (IT) – Infrastrukturen schwerwiegende negative Umweltauswirkungen: Vom Abbau von Konfliktmineralien über Kohlendioxidemissionen bis hin zu beträchtlichen Mengen giftigen Elektroschrotts. Andererseits werden IS als Schlüsseltechnologien für eine nachhaltige Wirtschaft gesehen. Umweltmanagementsysteme und die Umgestaltung von Geschäftsprozessen können den ökologischen Fußabdruck von Organisationen bedeutend verringern. Zudem eröffnen technologische Innovationen neuartige Möglichkeiten, die Umweltauswirkungen von Produkten und Dienstleistungen über den gesamten Lebenszyklus hinweg zu senken. Zahlreiche Organisationen haben damit begonnen, einzelne Green-IT-Maßnahmen zu implementieren um den Energieverbrauch und operative Kosten zu senken. Allerdings verfolgen die meisten Unternehmen hierbei keinen strukturierten oder strategischen Ansatz. Obwohl Green-IS-Initiativen beachtliche Potentiale zur Verbesserung der ökologischen Nachhaltigkeit von Organisationen bieten und gleichzeitig vielversprechende wirtschaftliche Chancen eröffnen, schreitet die Umsetzung von bereichsübergreifenden Green-IS-Maßnahmen in Unternehmen nur langsam voran. Ökonomische Unsicherheiten in Bezug auf die Rentabilität derartiger Maßnahmen sowie der Mangel an adäquaten Management-Frameworks werden in diesem Zusammenhang als zentrale Hinderungsgründe für eine strategische und ganzheitliche Umsetzung von Green-IS-Initiativen identifiziert. Diese Dissertation adressiert diese Hinderungsgründe, schafft Schlüsselkonzepte für den neuen Green-IS-Forschungszweig, entwickelt praxisorientierte Management-Frameworks und hebt die Bedeutung eines strategischen Ansatzes bei der Implementierung von Green IS hervor. Diese Forschungsarbeit offeriert empirische Einblicke wie auch konzeptionelle Modelle um die Umsetzung ganzheitlicher Green-IS-Initiativen in Organisationen voranzutreiben. Unternehmen haben somit die Chance, den Herausforderungen des Klimawandels verantwortungsvoll zu begegnen und gleichzeitig durch eine nachhaltige Unternehmensführung Wettbewerbsvorteile zu generieren.