In computer-mediated learning environments, especially in remote conditions, learners often lack the socio-affective cues that are usually available in face-to-face interactions. Socio-affective phenomena are known to play a prominent role at various levels of learning processes and outcomes, spanning high-order cognitive functions, motivation, sense of belonging, and quality of interaction with colleagues. Emotions, in particular, are nowadays considered dynamic and multifaceted phenomena that serve a wide range of adaptive functions. As a result, an interdisciplinary interest has recently emerged on ways by which computer-mediated learning environments may be endowed with emotional awareness, that is, information about one’s own emotions and/or the emotions of colleagues, which is instrumental to the learning task at hand. Emotion Awareness Tools are one such attempt to bestow learners with the possibility to produce and peruse emotional awareness through a dedicated interface that coexists with the overall learning environment. The thesis provides the details of the implementation and empirical assessment of an Emotion Awareness Tool with the following main characteristics. First, it is based on voluntary self-report of emotion. Second, it implements a computational structure of emotion rooted in appraisal theories of emotion, for which emotion elicitation and differentiation is a dynamic and ongoing process driven by a cognitive evaluation of the situation. Third, learners can produce and peruse emotional awareness through the tool on a moment-to-moment basis. Adopting an iterative design process, the implementation and assessment of the tool are guided by evidence gathered through empirical contributions aimed at investigating which factors – intrinsic to the tool, deriving from the interaction between learners and the tool, between learners themselves, as well as between learners and the instructional design – determine whether and how emotional awareness may be beneficial in computer-mediated learning environments. The main outcomes of the thesis are a toolbox that allows researchers and practitioners to configure an instance of the tool according to their own scientific or instructional goals, a structural causal model of the influence of emotional awareness on learning in computer-mediated environments, and methodological techniques or instruments that may be applied in similar contexts.