The energy systems of isolated areas are different from the stable energy systems of mainland areas. The particularity of isolated areas creates more risks for their energy systems planning, and the isolated areas can be considered to be a more specific analysis target than mainland areas. Various energy models and systems have been developed and applied in isolated areas. The major objective of this study is to provide a comprehensive literature review to identify, classify, evaluate and analyze the performance of different methodologies, models and energy systems for isolated areas. Therefore, effective information could be provided to support decision-making toward to appropriate energy models and systems for isolated areas with different scales and demands. This paper reviewed the forecasting techniques of energy demand and renewable energy (RE) resources, energy models, application of hybrid RE systems (HRESs), and management of energy planning for two most representative isolated areas: islands and remote villages. The uncertainty analysis of energy systems of isolated areas is also discussed. It is evident that the indigenous RE resources show great potentials for the energy system of isolated areas, especially the solar and wind resources. The various combinations of photovoltaic (PV), wind, diesel and batteries have been proven more competitive. Also, it is necessary to develop sophisticated models that are more applicable to isolated areas and that consider the distinctive characteristics, practical needs and uncertainties of isolated areas.