The focus of this thesis is social marketing in general and behaviour changing campaigns in particular. The purpose is to examine how such campaigns with a large target group are able to change the behaviour of individuals by the use of non-financial incentives. The particular behaviour focused on is littering in cities, as this is a considerable problem in many places. This is done within a theoretical as well as a social context. The theoretical approach focuses on how social marketing is able to solve the conflict between the present behaviour of the individual and the desired behaviour of the campaign when trying to change the behaviour of the target group. This is done by including psychological phases within behaviour change as a part of a social marketing plan in order to use the individual and his present situation as the point of departure. Furthermore, different means to creating attention and motivation are analysed in the form of relevance and cost/benefit strategies. The analysis shows that the present situation and behaviour of the target group should be the starting point for any behaviour changing campaign. Otherwise the campaign may not be able to reach its target group properly with a lack of effect as a result. Behaviour changing within a social context is analysed by the use of litter campaigns from Copenhagen and Scotland, the empirical basis being the websites of these campaigns. The theoretical concepts are integrated in this analysis as a way of uncovering these campaigns’ abilities to change the behaviour of their target groups. They primarily appear to be aimed at an individual not yet aware of the consequences of his littering. This is seen in the way they first and foremost try to create awareness of the littering problems in cities instead of creating opportunities for a new behaviour, the campaigns’ desired behaviour, not involving littering. A main difference between the campaigns is Copenhagen’s primary focus on the desired behaviour and Scotland’s primary focus on the present behaviour in their attempt to change the behaviour of their target groups. The analysis of changing litter behaviours results in the conclusion that a point of departure in the target group’s present behaviour and mindset is essential to create the rectifying effect sought by campaigns within this line of social marketing. However, the problem might be, as seen with the campaigns in Copenhagen and Scotland, that campaigns are aimed at the segment least likely to change their behaviour which inevitably delays the outcome of a possible behaviour change.