This chapter introduces the study of tourism impacts. It shows that although tourism impacts tend to be multi-faceted, it is conventional to subdivide them under the following headings: economic, socio-cultural and environmental. The chapter presents tourism impacts as either positive or negative. Ideas put forward by B. McKercher on the commercial and entertainment aspects of tourism have also been introduced and these have been considered in relation to tourism impacts. The chapter suggests that it is important to note that much tourism planning and management occurs in relation to impacts at tourism destinations. Tourism takes place in the environment, which is made up of both human and natural features. The human environment comprises economic, social and cultural factors and processes. Tourism, as a significant form of human activity, can have major impacts. These impacts are very visible in the destination region, where tourists interact with the local environment, economy, culture and society.