Existing research predominantly focused on aspects of emotional intelligence (EI) such as perception and regulation of emotion in individuals with bipolar disorder (BD). Moreover, previous research used participants with BD as a clinical control group when studying other types of psychiatric disorders, for example schizophrenia and unipolar depression. Therefore, the current research aimed at investigating all aspects of EI (perception and understanding, use of emotion to facilitate thought and regulation) in individuals with BD. The first study was a questionnaire-based quantitative study that aimed to identify if individuals with BD differ in their EI from people in the general population and find if participants' responses indicates a relationship between EI and alexithymia. Study two was an experiment that measured perception and recognition of emotion with a face emotional performance recognition accuracy, error and response time task. Study three was qualitative. It aimed to provide an in-depth understanding of positive and negative emotions in individuals with BD. The questionnaire-based study had 96 participants; participants with BD (n= 44) were recruited through support groups, and the remainder (n=52) were adults from the general population (controls). Thirty-five participants from the questionnaire-based study participated in the experiment and qualitative studies. In study 1, the results show that individuals with BD had a low level of EI in comparison to healthy controls. In addition, individuals with BD had more emotion regulation difficulties. Thirdly, alexithymia was negatively correlated with EI. Lastly, correlation analysis found mood symptoms of BD (depression and mania) to be correlated with EI, particularly depression. In study 2, participants with BD did not differ from the controls in their emotion recognition accuracy and the BD group had significant misattributions of anger. In study 3, three themes emerged from semi-structured interviews with individuals with BD and controls: emotion recognition, psychological wellbeing, and psychological states. In conclusion, the findings showed that people with BD have limited levels of EI. Therefore, psychological treatment for people with BD should focus on facilitating improvement of EI, and prevention of maladaptive strategies to communicate and deal with emotion. Future research could build on these findings, for example through researching what strategies to communicate and deal with the emotion individuals with BD are likely to adopt in the phases of BD.