Emotional intelligence (EI) describes the ability to perceive, understand and regulate one’s own and others’ emotions and to integrate them purposefully into thought and action processes. This chapter first summarises the current state of research on EI from psychological, neuroscientific, and technological perspectives. It explains the neurobiological foundations of emotion processing and its significance for adaptive social interactions, followed by a presentation of key theoretical models that explain EI and make it usable for the development of measurement instruments. The chapter then presents and critically reflects on established methods for measuring EI. Particular attention is paid to the integration of these concepts into the field of artificial intelligence (AI). Systems that recognise, interpret, and adaptively respond to human emotions open up new possibilities for personalised interactions, but at the same time pose considerable ethical challenges. Fields of application such as telemedicine, mental health, and digital customer services are illustrated with specific case studies. The discussion includes the role of explainability, fairness, and data protection in the development of human-centered AI (HCAI) systems. Finally, HCAI guidelines for responsible design are presented, focusing on the protection of human dignity and the preservation of cognitive autonomy. In this way, the chapter contributes to the interdisciplinary debate on the connection between basic psychological research, technical implementation, and social responsibility, and aims to provide an overview of theoretical approaches, empirical findings, and practice-relevant concepts that are of central importance for the design of trustworthy AI systems.