Meta-organizations, organizations made of other organizations, constitute an important and multifaceted phenomenon of contemporary and globalized societies. We can find meta-organizations everywhere, in all spheres of society, at all levels, in all contexts and countries, from international oil and gas business associations to national crowdfunding associations, local fisheries co-management committees in Catalunya and translocal indigenous communities associations in Amazonia. Meta-organizations differ both from organizations made of individuals, e.g., firms, associations or social movements, and from non-decided orders, e.g., networks or institutions. The specific nature of meta-organizations, i.e., being an organization, being made of other organizations, and being associative or collaborative, has key theoretical implications. Most conventional or dominant theoretical approaches do not fully account for these implications. Meta-organizations are extremely diverse, something that no theory has been able to grasp so far, for a lack of an overarching approach. Meta-organizations fulfill different purposes, conduct various activities, and exhibit high variations in establishment, membership composition, segmentation, scale and scope, perimeter of action, mandate and issue specificity, and sectoralization. In my research, I mostly draw from Ahrne and Brunsson’s work. However, I noticed an evolution in my general framing. In Phd thesis, I started from a more strategic management and a collective strategies approach, using the lens of socio-technical analysis (Akrich, 1991; Akrich et al., 2006). I then shifted to a more organization studies and organizational sociological approach, with a focus on social orders. I drew from boundary disciplines or fields, like communication as constitutive of organizations (Dobusch & Schoeneborn, 2015), system theory (Grothe-Hammer et al., 2022; Luhmann, 2018), political science (Jordana, 2017; Mathieu et al., 2016), alternative organizations (Varman & Vijay, 2022b), or transition studies (Geels et al., 2016). Concretely I am interested in why meta-organizations exist and what they can (and to a lesser extent cannot) do for sustainability transitions. In my Phd thesis, I asked whether meta-organizations made the idea of sustainable development performative. Then, I kept approaching this question of transformation towards more sustainable and just futures through different angles: sustainability transitions, grand challenges or complex problems, ocean governance, crowdfunding, biodiversity conservation, etc. Having this in mind, and as Figure 1 synthesizes, my research trajectory can be thought of as four interconnected building blocks: 1) meta-organizations as an important empirical phenomenon (i.e. a descriptive approach of what meta-organizations are, how diverse they are and what they do), 2) meta-organization as a concept (i.e., a more analytical approach), 3) meta-organization as a theory (i.e., a more theoretical approach), 4) meta-organizations as part of the problem (i.e., a more normative and critical approach). These building blocks constitute the backbone of my dissertation.