According to the Center for Disease Control and Prevention (2017), over 14% of the US population practice mindfulness meditation. The effects of mindfulness-training on physical and mental health have been consistently documented, but its effects on interpersonal relationships are not yet fully understood or investigated. Interpersonal relationships play a crucial role in the well-being of individuals and society. The aim of the current project is to study the interpersonal effects of mindfulness-meditation training and the psychosocial and brain mechanisms behind these effects. Using a multidisciplinary method that studies subjective self-reported experience and objective behavioral-observation, we aim specifically to understand how mindfulness-meditation training impacts social emotional regulation, empathy, active empathic listening, social-emotional support, compassion towards others, perspective-taking, and mindful-responding. We aim as well to study the indirect impacts of mindfulness-meditation training on others’ emotional states. Therefore, the proposed project extends the study of mindfulness from the intrapersonal to the interpersonal domain, specifically the impact of mindfulness-training on the interpersonal-interactions with others and their well-being. The proposed project has important academic and social implications and will allow devising new and more effective interpersonal mindfulness-programs with applications in multiple fields, including parenting, teaching, counselling, management, physical/mental health, and intimate/conjugal relationships, among others.