Internationally, the pharmacy profession’s paradigm of practice has been shifting from a product-oriented role to a patient-oriented role. Despite increasing public interest, there has been a lack of research into the experiences of pharmacists as they make the transition to a patient-oriented role. Furthermore, it is important to understand how individual pharmacists construct their identity in making this transition, as well as how they behave or react within the role prescribed by their work contexts. This issue of analysing identity construction at the personal level, especially in professionals, is one which empirical research has failed adequately to investigate. With a focus on Thailand, this research thus explores how the paradigm shift to a patient-oriented role influences pharmacists’ identity construction in two different work contexts: a public hospital setting and a private drugstore setting. This enables a comparison of how pharmacists construct identities differently in the two contexts, thus highlighting how a particular context influences individuals’ identity construction by providing multi-discursive resources. This thesis employs negotiated order theory and the social arena concept to examine how pharmacists negotiate to establish their role boundaries, and how they engage with the consequences of these role boundaries. It is found that pharmacists construct identities differently, depending on the context in which their role is situated. Consequently, identity construction is influenced by personal identity, role identity and work and family contexts, as well as professional values. In summary, this thesis contributes to currently under-researched areas of the pharmacy profession literature associated, in particular, with identity and negotiation. At the theoretical level, the thesis also sheds light on using negotiated order theory and the social arena concept to examine negotiations in the less institutionalised context of private drugstores. Finally, the thesis offers a more comprehensive model for identity construction, which includes the role of personal identity, role identity, contexts and social interactions to explain how pharmacists construct their identity, and in so doing highlights the dynamics behind the identity construction process.