In this chapter I address the state of the art and future potential for data aggregation on global level of volunteering (Wilson, 2000; Butcher Einolf, 2017; Guidi et al., 2021b), under the assumption that voluntary action (Fonović, 2023, pp. 21–42) of citizens for the common good is not merely a “renewable resource” of the nonprofits (Salamon et al., 2018) but the very “source” and the basic building block of civil society and of the Third Sector as such (UN, 2018). Therefore, the possibility to rely on “good” data on volunteering in globally comparable dimensions can contribute significantly to studying different facets of the Third Sector. Data on volunteering can be put to good use in a variety of disciplines, either as input, for example in approaches as diverse as development, democracy or management, or as output, for example in approaches as diverse as political history or psychology. The aim of the chapter is to clarify what comparable data can be generated by national statistical institutes following the ILO methodology on volunteer work (ILO, 2021) and to propose a method for a collaborative effort for refining and advancing this tool.