Issue No. 47 of the International Journal for the Portuguese Language (RILP) emerges at a moment of great relevance for global debates, with the theme “Sustainability and Social Development. In a context marked by environmental and social challenges, reflecting on these concepts becomes not only necessary but urgent. This issue brings together a series of articles that, from an interdisciplinary perspective, seek to analyse and propose solutions for the complex links between environmental sustainability, social development, and their impacts within the educational sphere. Sustainability, in its broadest definition, involves the pursuit of a balance between the environment, the economy, and human well-being. However, it is important to emphasise that, in practice, it cannot be dissociated from social and educational issues—especially in a context where inequalities persist and are deepening in many parts of the world. Social development, in turn, is not limited to economic growth. It also encompasses inclusion, equity, the improvement of living conditions, and the strengthening of human capabilities.