As a result of the pervasiveness of smartphones and improvement of context-aware systems, developers have designed and implemented a variety of context-aware tour guide systems. These systems focus on tourist attractions and provide services for tourists in order to support them before, during and after the trip. This survey aims to summarise, classify and investigate these systems from three standpoints of general, design and context-related issues. To this end, after introducing the related concepts, a framework for investigating context-aware tour guide systems is proposed. The aim is the theoretic consideration and classification of these projects with regard to distributed and pervasive computing patterns and the identification of the current situation and challenges. The proposed framework includes three axes of general, system design and context- awareness, each of which consists of some parameters. Afterwards, the existing projects are categorised according to the proposed framework. Finally, concluding remarks as well as new trends are discussed in order to illuminate future research directions.