Sustainable development poses a grand challenge for society, addressed by organisations through their public relations activities. Grand challenges are complex by nature and call for nontrivial solutions whose effects show at the level of society. That is why studying public relations’ contribution to grand challenges requires a macro perspective that accounts for the dynamic interaction between individual, organisational, and system levels in a digital communication environment. This paper offers a new paradigm to analyse organisations’ significant and at times undue impact on grand challenges through public relations. It develops a framework inspired by complex adaptive systems thinking and adopts its ten properties for public relations: emergence, adaptivity, heterogeneous actors, nonlinear effects, feedback mechanisms, self-organisation, phase transitions, networks, scaling, and cooperation. The paper applies the framework to the example of sustainable development. It shows why research on grand challenges requires a holistic perspective and how it can help study digitally born communication phenomena. The proposed complex systems paradigm provides space for critical, social scientific,
and interpretative research lines in public relations. Inquiries start from the grand challenge and study the communicative interactions between organisations and other actors from existing theory while accounting for the ten properties of complex adaptive systems. The paper outlines how future research can enrich the study of public relations and discusses its limits.