This chapter is concerned with the WHO and UNEP as examples of advocate–style IPAs. These IPAs share behavioural patterns that have allowed them to establish themselves as ‘advocates’ in the area of environmental and global health matters. Despite their apparent common capability of solving problems of global scale, the two IPAs could hardly be more different when considering only their structural features. We show that this commonality in styles, despite structural dissimilarities, is due to the similarly strong perception of external threats and the comparatively low level of internal challenges. Strong expertise and a common belief system contribute to the formation of an advocacy–orientated administrative style while at the same time, a medium level of perceived external challenges prompts both IPAs to also feature at least some characteristics of a consolidator.