There is an exponential growth in lived experience work in the field of mental health, education, and research. Those in lived experience roles are people with personal experience of services and disabilities that use their experiences to help inform service provision that better meets the needs of other service users. The lead researcher has engaged in this type of work herself and noted that it made a profound impact on her identity. However, the current theoretical framework on identity including social identities and role identities, do not account for identities that span service user and service provider, as they are typically considered binary and oppositional. Therefore, this thesis aimed to explore and give greater clarity to the identities within this sector, how they can work together more effectively, and to better support the process of lived experience work. To explore this, Study 1, a systematic review of the literature was conducted to understand the identities of lived experience researchers and providers. The EMERGES framework was developed, encompassing, Empowerment, Motivation, Empathy of the self and others, Recovery model and medical model, Growth and transformation, Exclusion and Survivor roots, factors influencing identity. The findings suggested that identity in the field of clinical psychology was under researched, providing the rationale to study the collective identity of clinical psychology training and its subgroups of Experts by Experience, Expert Carers, Trainee Clinical Psychologists and Experts by Qualification in separate focus groups in Study 2, to observe how their identities were socially constructed. It was hypothesized that the process of identification between trainees and their trainers would be influenced by individual differences in mental health and professional identities and personality differences which was tested in Study 3, a pilot study. Quantitative methods were used to understand how trainee clinical psychologists identified with these trainers. An in-group identification measure for trainee clinical psychologists was tested for reliability and validity. The study found three factors of cognitive, affective, and evaluative identification. Study 4, a preliminary study, gathered findings from across the thesis to understand lived experience researchers' needs from supervision using Q methodology. Three types of lived experience researchers were found, the first focused on developing their skills, identity, growth, and empowerment, the second focused on understanding their relational and emotional link to the research, and the third focused on support to navigate personal and professional identities in practical and emotional ways. Together these studies provide insight into the identities in mental health, education, and research and ways to forward lived experience work.