Interactions between wildlife and tourism can be studied from several different perspectives and the effects of such interactions can influence animals both positively and negatively with effects on both individual and population levels. This thesis takes an interdisciplinary approach, combining both natural and social perspectives, when studying the effects of tourism activity on a small population of the endangered arctic fox (Vulpes lagopus). We have studied arctic foxes inhabiting disturbed and undisturbed den sites in Helagsfjällen, which is the southernmost population of arctic foxes in Sweden and a popular area for recreational activities such as hiking, skiing and camping. The overall objective of the thesis has been to contribute to good management of both arctic foxes and tourism within the study area, as well as to contribute with a comprehensive study of simultaneous disturbance effects and fitness consequences of wildlife tourism activities to the scientific field of wildlife-tourism interactions. The first two papers focus on different aspects of behavioral responses of arctic foxes towards human activity, the third paper evaluates potential fitness consequences and the fourth paper focus on the tourist aspect of the interaction. Behavioral changes in response to tourism disturbance that have been identified in the foxes include changes in vigilance and probability of hiding (Paper I), temporal activity shift at the den site (Paper II) and increased tolerance to human activity (Paper I, Paper II). Juvenile summer survival was higher at disturbed dens compared with undisturbed dens during years of declining small rodent densities (Paper III). Small rodent decline years is when the predation on arctic foxes is presumed to be highest and we suggest that the positive fitness effect could be mediated by a human-induced predator refuge for the foxes in close proximity of human activity. On the tourist aspect, we have identified effects on behavior, knowledge and awareness of the situation for arctic foxes and related conservation work (Paper IV). Overall, results in this thesis showed a high level of context-dependency, which highlights the importance of considering factors such as food availability, intra-species interactions and individual traits such as previous experience with humans. Consequently, the work in this thesis together with ongoing studies of hormonal stress responses constitutes one of the more comprehensive scientific studies of tourism effects on terrestrial mammals. The output from this thesis brings important deliverables for species-specific management and conservation, but also for other species given the rapidly growing interest for wildlife tourism.