In this chapter, we discuss the creative class theory developed by Richard Florida (2002, 2005, 2014) with a special emphasis on the Global Tolerance Index (GTI). The key proposition of his theory is that the so-called 3T’s - Technology, Talent and Tolerance - are key drivers for economic growth. Places that are more tolerant of people with diverse backgrounds have a competitive advantage as they will attract more talented people from ‘the creative class’ who in turn develop innovative ideas that enhance prosperity. We first outline the cornerstones of Florida’s theory, explain the composition of the Tolerance Index developed for the US-context as well as the GTI and discuss the global tolerance country ranking, which covers 139 nations. We then show how the index has been applied, discuss its strengths and weaknesses and finally outline some avenues for future research that embrace tolerance in the context of multi-disciplinary and multi-level D & I research.