This chapter, given over to the application of economics and sociology of conventions to countries of the Global South, begins with an outline of thetradition shared by convention theory and heterodox development economics (Sect. 2). The overview of this shared vision takes as its starting point the work of Albert Otto Hirschman, one of the most influential economists in the heterodox strand of development economics. Section 3 illustrates the relevance of applying convention theory to the countries of the Global South, taking the example of three sectors that are particularly crucial in the field of development, namely, healthcare, energy, and food. Finally, in Sect. 4, the argument is widened by showing what convention theory contributes to development economics and what the countries of the Global South have contributed to the framework in terms of conventions. Several areas of progress are highlighted, such as perceptive studies of the relations between actors with different values, analyses of global power relations, and the questioning of the dominant paradigms by means of a pragmatic rather than overarching empirical method