There are few actors as predestined to assume authority in global governance as transnational religious actors (TRAs) are. Such actors can have a global reach; they provide guidelines on societal interaction within and beyond their own religious community; and they posit ideas on the handling of public goods - such as the climate - at a global level. TRAs have actively contributed to shaping global governance institutions such as those on combating climate change. Yet, there has been no attempt to conceptually integrate religious authority in global governance (GG) approaches. This paper therefore introduces the concept of religious authority by building upon the established elements of authority (power, legitimacy, public interests) and focusing on the link between moral authority, global common goods, and in/formal means. The paper is divided into two parts: while the first part abductively establishes what characterizes religious authority in global governance, the second part presents a case study which demonstrates how TRAs exert this authority in the area of combating climate change. This is a strong case for religious authority as it illustrates how religious groups join forces based upon converging understandings of caring for creation. Not only were they successful in mobilizing forces beyond their own religious communities, but they effectively shaped how this issue was framed and tackled by the United Nations. The findings of these two parts are brought together in a discussion on whether religious authority constitutes a unique form of authority and what lessons other types of global governance actors can learn from religious actors in GG.