Human facial movements transmit a wealth of dynamic signals that provide crucial information about people’s emotional states. The temporal dynamics of facial expressions of emotion are optimised to hierarchically transmit biologically rooted and socially adaptive signals over time. We begin this chapter by formally defining these signals and by offering an overview of recent advances in research methods that improving our understanding of them. We then describe how the ability to decode such biologically relevant social signals emerges early in life and evolves throughout adolescence. Next, we discuss how experience, culture, and individual differences shape the decoding of facial expressions of emotion, before moving towards differences in processing static and dynamic facial expressions of emotion. Finally, we elaborate on the use of more ecologically valid experimental designs, cross-cultural studies, and understanding the roots of individual differences in facial expression processing to improve future knowledge in the field.