Emotions help in steering and tuning our behavior in social situations. Attention to emotional states of others, emotional responsiveness towards others, and adequate regulation of emotions is crucial for adaptive social functioning, already from an early age. It is therefore important to study emotion processing in individuals with autism spectrum disorders (ASD). Techniques from the field of neuroscience, i.e. eyetracking and biomarkers of the autonomic nervous system (heart rate and skin conductance), have provided us with sensitive and objective means of assessing this. The key focus of this symposium is understanding the nature of emotion dysfunctions in individuals with ASD across a range of developmental stages: infancy, childhood and young-adulthood. Using biomarkers and eyetracking parameters, insights in emotional responsiveness, the regulation of emotions and stress, and attention to emotions of others will be presented. This approach might help in identifying the specific nature of socio-emotional difficulties in ASD beyond the behavioral phenotype.