Facial expressions play an important role during human social interaction, enabling communicative cues, ascertaining the level of interest or signalling the desire to take a speaking turn. They also give continuous feedback indicating that the information conveyed has been understood. However, certain individuals have difficulties in social interaction in particular verbal and non-verbal communication (e.g. emotions and gestures). Autism Spectrum Disorders (ASD) are a special case of social impairments. Individuals that are affected with ASD are characterized by repetitive patterns of behaviour, restricted activities or interests, and impairments in social communication. The use of robots had already been proven to encourage the promotion of social interaction and skills in children with ASD. Following this trend, in this work a robotic platform is used as a mediator in the social interaction activities with children with special needs. The main purpose of this dissertation is to develop a system capable of automatic detecting emotions through facial expressions and interfacing it with a robotic platform in order to allow social interaction with children with special needs. The proposed experimental setup uses the Intel RealSense 3D camera and the Zeno R50 Robokind robotic platform. This layout has two subsystems, a Mirroring Emotion System (MES) and an Emotion Recognition System (ERS). The first subsystem (MES) is capable of synthetizing human emotions through facial expressions, on-line. The other subsystem (ERS) is able to recognize human emotions through facial features in real time. MES extracts the user facial Action Units (AUs), sends the data to the robot allowing on-line imitation. ERS uses Support Vector Machine (SVM) technique to automatic classify the emotion expressed by the User in real time. Finally, the proposed subsystems, MES and ERS, were evaluated in a laboratorial and controlled environment in order to check the integration and operation of the systems. Then, both subsystems were tested in a school environment in different configurations. The results of these preliminary tests allowed to detect some constraints of the system, as well as validate its adequacy in an intervention setting.