This thesis explores the relationship between culture and development as reflected in the current international debate on human and sustainable development through the lens of the EU's external policy practice. For long time culture has been kept aside from the international debate around development, yet, during the last twenty years, culture become considered a relevant vehicle to promote human sustainable development and nowadays many voices at local and global stages argue for recognizing culture as the fourth pillar of sustainable development and call for a greater integration of culture into developmental policies. Although culture as a driver and enabler of sustainable development is rather peacefully accepted, mainstreaming culture within developmental policies is a considerably challenging task. This often implies confronting contradictions and tensions, arising, in particular, when culture interacts with trade and other aspects of today's global economy. The debate around the need to promote culture as a vehicle for development highlights the need to intensify cultural flows at the global level. On the other hand, the unbalanced access to global trade and the unfair relationship between developed and developing countries raise issues concerning the protection and promotion of less economically important cultures. A balance between the interest to foster cultural exchanges and to protect cultural diversity needs to be found. The European Union, as a major international actor on the international scene, is taking part to the global debate about mainstreaming culture in developmental policies. In particular, the Union's external initiatives concerning the role of culture in contributing to sustainable development has gained strength since the EU's ratification of the UNESCO Convention for the Protection and Promotion of the diversity of cultural expressions (2008). This thesis develops around the following questions: is the EU – as a global actor – carrying out a coherent policy when mainstreaming culture as a vector of development in its external action? If not, how can the Union improve the mainstreaming of culture as a vector of development in order to pursue a more coherent approach? The analysis carried out in this research tries to answer this main question by analysing the EU's action in three specific cases dealing with the interaction of culture with development, namely the free circulation of cultural goods and services, the mobility of artists and cultural professionals, and the protection of traditional knowledge related to the use of genetic resources. The thesis demonstrates that, although the inner institutional and constitutional features of the EU often hamper the achievement of an overall coherent EU policy, the Union is certainly contributing to the shaping of a global governance for "culture and development". The thesis also argues that the overall action of the Union could gain added value from a better use of the principle of integration and, more broadly, the principles of sustainable development.