Understanding others’ emotions and false beliefs, known as Theory of Mind (ToM), and to recognise and produce facial expressions of emotion has been linked to social competence. Deaf children born to hearing parents have commonly shown a deficit, or at best a delay in ToM. The emotion processing skills of deaf children are less clear. The main aims of this thesis were to clarify the ability of emotion recognition in deaf children, and to provide the first investigation in emotion production. While deaf children were poorer than hearing controls at recognising expressions of emotion in cartoon faces, a similar pattern was found in both groups’ recognition of real human faces of the six basic emotions (happiness, sadness, anger, fear, disgust and surprise). For deaf children, emotion recognition was better in dynamic rather than static, and intense rather than subtle, displays of emotion. With the exception of disgust, no differences in individual emotions were found, suggesting that the use of ecologically valid dynamic real faces facilitates deaf children’s emotion recognition. Deaf children’s ability to produce the six basic emotions was compared to hearing children by videoing voluntary encodings of facial expression elicited via verbal labels and emotion signed stories, and the imitation of dynamic displays of real facial expressions of emotion. With the exception of a poorer performance in imitation and the verbally elicited production of disgust, deaf children were consistently rated by human judges overall as producing more recognisable and intense expressions, suggesting that clarity and expressiveness may be important to deaf individuals’ emotion display rules. In line with previous studies, results showed a delay in passing the first and second order belief tasks in comparison to age matched controls, but not in comparison to a group of ‘age appropriate’ hearing control children. These findings encouragingly suggest that while deaf children of hearing parents show a delay in ToM and understanding disgust, emotion processing skills follow a broadly similar pattern of development to hearing control children. Language experience is implicated in difficulties faced in social and emotion cognition, with reduced opportunities to discuss more complex emotional and mental states.