In this chapter the authors discuss the emotional power of the singing voice. The chapter begins by providing an overview of the process of externalization of emotions by the human voice. Then, the authors discuss some fundamental determinants of emotional expression in singing, namely the ‘emotional script’, the artistic interpretation, and the singer’s affective state. Next, they describe the manner in which expressed emotions are encoded in the voice by singers and recognized by listeners, and compare it with vocal expression in everyday life. Finally, they identify various methodologies that can enhance understanding of the physiology of vocal production and the acoustic cues fundamental to perception and production of expressive sung performance. The authors propose that the knowledge gained from application of these methodologies can inform singing practice, and that interdisciplinary approaches and cooperation are central aspects of a fruitful and sustainable study of the expressive powers of the singing voice.