The Travel & Tourism Competitiveness Index (TTCI), developed by the World Economic Forum (WEF), is a composite indicator that integrates a total of 90 simple variables organized into 14 pillars or key dimensions of the tourism destination competitiveness. The main problem presented by this index comes from the aggregation of variables expressed in different measures, the duplicity of information, and their non-weighting in the synthetic index. This chapter proposes a new methodology for the construction of the TTCI that solves the previous problems and allows, in addition, identifying which are the pillars or dimensions that determine the differences in tourism competitiveness between the countries. The results have allowed authors to more precisely classify 136 countries according to their level of tourism competitiveness in 2017. To improve the tourism competitiveness of the countries, it is necessary to carry out policies that act on these pillars and others identified in this chapter.