The way people communicate is closely tied to the expression of their emotions. Facial expression analysis has become a hot study issue in recent years, with applications in a variety of fields, including the Human-Computer Interaction (HIC). Thanks to Computer Vision technologies, Facial Expression Recognition (FER) uses algorithms to analyze faces in images or video, integrating the visual world with computing systems through the simulation of human vision. FER employs facial feature and movement analysis to recognise emotional expressions. FER analysis consists of three steps: Face Detection, Facial Expression Detection, and Expression Classification into emotional states. There are many reasons why interpreting emotions from Facial Expressions may not always be accurate as mix different emotions at the same time or sociocultural and contextual factors.