Sustainable consumption is seen as a crucial political issue on the global agenda by politicians, the scientific community, and citizens who are worried about unsustainable consumption. However, several studies have shown that some consumers with "green" values do not consume sustainably – there is often a gap between attitude and behavior. One explanation is that the commitment to sustainable consumption is discouraged by barriers to action. For example, the supply of sustainable goods may be inadequate or the products too expensive. Such goods may be perceived as ineffective in their purpose to promote sustainable development, or perhaps it is believed that there are not enough other people who consume sustainably to make the individual effort worthwhile. However, some studies have indicated that there are also "reverse gaps". That is, there are people who are not particularly motivated to engage in sustainable consumption, but who do so anyway. The study examines why consumers sometimes engage in sustainable consumption (operationalized as a choice of environmental and Fairtrade certified products) but do not at other times. Research questions include which individual prerequisites (motivation and resources) are important for sustainable consumption, how they are distributed among citizens in Sweden, and finally whether perceived opportunities for sustainable consumption can form not only barriers but also "bridges" for engagement and how these are formed. The latter could explain the "reverse gaps" mentioned above. The author builds on the discussion about the challenges that sustainable development poses for the concept of citizenship. Researchers argue that sustainable development requires a transformation of traditional citizenship theory into a "sustainable citizenship". This is not limited by nation-state borders, takes into account past and future generations, and is open to the idea that responsibility-taking can, and sometimes should, be carried out in the private sphere. The dissertation is based on quantitative analysis of a (Swedish) representative survey and shows how consumers can be divided into different clusters based on their individual prerequisites: "Capable Critics", "Capital Weak Critics", "Conditionals" and ”Skeptics". Even if it is only the Capable Critics who have both the high motivation and a high level of resources that theoretically could be assumed to be necessary, there are a significant amount of consumers who choose environmental and Fairtrade labeled goods regularly across all clusters. These types of consumers encounter bridges to action by particularly positive perceived opportunities that make the engagement a little less demanding on individual prerequisites. The bridges are not the same for all clusters though. Their particular approach to sustainable consumption determines which factors are most important. / Det hållbara medborgarskapet