Economic, social and ecological sustainability presents one of the greatest challenges of our society. As a result, there is growing pressure on a variety of organizations to implement sustainability programs, such as inclusion training related to social sustainability, cost management programs related to economic sustainability, and perhaps most importantly, green (information) systems related to environmental sustainability. Not only is multifaceted sustainability most beneficial to organizations at large, but also there are several categorical thresholds that organizations must meet in order to be certified. For these reasons, companies are increasingly adopting information systems (IS) for sustainability in their operations. Specifically, programs designed to influence employee motivation, attitudes, beliefs, and behaviors are gaining attention. While there is a long tradition ofresearch on technology adoption, such sustainability systems harbor several new phenomena, both with respect to individual and organizational adoption. Therefore, in this study, we explore the challenges of adopting sustainability systems in organizational contexts. Using activity theory and innovation diffusion theory, and with technology adoption theory as the backdrop of our investigation, we conduct a qualitative field study in four small- and medium- sized companies. Using both theory-guided deductive and inductive interpretation phases, we illuminate adoption challenges through combined intersections of adoption stages (knowledge, persuasion, decision, implementation, and confirmation) and activity domains (subject, instrument, object, community, rules). We then shed light on the severity and importance of these challenges through an expert validation study with green IS experts. In discussing the challenges in light of motivational and green IS design, we posit four dilemmas in green IS adoption that arise from tensions in the specific context of sustainability in organizations. Our findings expand existing knowledge in research on green IS, motivational IS design and sustainable behavior change interventions and yield several theoretical and practical avenues for future inquiry and endeavour.