Over the past 100 years, urban planners have been promoting a variety of new urban forms, called inter alia Sustainable, Green, Low Carbon, Livable, and Eco-cities, to improve the quality of life of citizens and the local and global environment. Numerous indicator systems have been developed to evaluate the implementation of these theories. The popularity of indicator systems is increasing as local and global constituents give greater attention to mitigating and adapting to climate change, environmental damage and resource constraints. However, no two systems are alike. Each system differentially includes, categorizes and prioritizes indicators, making it difficult to define an eco-city and evaluate the status and progress of developments. This paper evaluates the structures and component indicators of 16 international municipal-level sustainable, green and eco-city indicator systems from the last several years. While there is some consensus regarding the most important elements in determining city sustainability, there is little agreement on the method by which indicators are chosen, the weights assigned to indicators, and the best indicators themselves. Key conceptual frameworks and indicator categories are isolated and evaluated for common elements and the results are compared to other studies. The analysis of best-practices suggests that a set of standardized core indicators need to be developed first, and then enhanced with locally-relevant indicators. Ranking could be postponed until empirical data establishes causal connections between indicators and outcomes. The findings from this study will be used to further develop a low-carbon eco-city indicator system for China.