Purpose and Originality: ‘Greenness’ and sustainability are moving from an abstract concept toward a measurable state, using the triple bottom line approach considering environmental, social, and economic dimensions. How the ‘greenness’ and sustainability of Ljubljana, the capital of Slovenia, are achieved and estimated, is determined by comparing two indices. European Green Capital Award represents its‘greenness’, while its sustainability is analysed by A New Sustainability City Index Based on Intellectual Capital Approach. Originality of the research is the analysis of the potential of Ljubljana city through contrasting these two indices. Method: Quantitative and qualitative methods were used. Two comparable indices have been chosen as a multidimensional concept which both clearly involve economic, environmental (ecological) and social aspects, with available and published results for Ljubljana. Both indices are comparable, the category scores were aggregated according to equal weighting, and the index results were expressed as percentages. Results: The results showed that ranking of Ljubljana as a‘green’ and sustainable city respectively is different. Total index score of 52 % for European Green Capital Award places Ljubljana 22ndamong the ‘green’ cities of Europe and ranks it in the upper half of the 58 European cities in the study. A New Sustainability City Index Based on Intellectual Capital Approach x of 44.92 ranking Ljubljana on the 102nd position in a scale of 158 European cities, places it in the lower half. The results confirm that Ljubljana is more ‘green’ than sustainable, according to these studies. Society: There are many studies, which make a concerted effort toward capturing the ‘greenness’ and the sustainability of cities. Therefore, indices include three independent dimensions and are decisive in positioning the city. These are important tools in making environmental (ecological), social-cultural, and economic decisions in cities’ policy, which directly affect companies, management and society. Limitations / further research: The main research limitation of this proposal is unavailability of complete database for both indices. Further research is more than needed, with the most recent available data.