Over the last three decades, the production of soy has become an increasingly lucrative business in Brazil and Argentina. Now fully incorporated in globalized production networks, local consequences of global activities are observed; socio-territorial fragmentation, increasing vulnerability, rising polarization between socio-spatial inclusion and exclusion, and the manifestation of socio-ecological conflict constellations become core problems of investigation. In this context, discussions on fairness have become increasingly relevant in the production of and discourse on soy (e.g. RTRS, 2015). In this chapter, we compare two soy frontiers: the Mato Grosso Region in Brazil and the Argentine Chaco. At first glance, the two regions seem to undergo similar patterns of development, experience the same challenges and conflicts, and deal with issues of (un)fairness and (in)justice in similar ways, that is, mostly in the form of non-response and non-articulation of environmental justice claims. However, on a closer look, there are important differences in the two countries related to different national agendas, foci, and socio-environmental frameworks, for example, fiscal export policies or migration and spatial reconfiguration patterns. These differences are also reflected in the multiplicity of approaches and meanings of ‘fairness’. The objective of the chapter is twofold. First, the two soy frontiers are compared in order to unearth particular regional characteristics. Second, it is shown that fairness should be treated more as a ‘conception’ (an individual or group’s perception of a concept) than as a ‘concept’, since the understanding of what is considered ‘fair’ is context-related and perspective-based. In this vein, activist-driven environmental justice concepts help to develop arguments of what fairness could look like in different contexts and from different perspectives. However, they are limited in analytical scope since situations of non-articulation of socio-ecological claims are not considered. Such elements, however, are of high importance in our case studies.