Background: Non-technical skills have seen increasing interest within patient safety research specific to some roles within healthcare, with behavioural marker systems produced that can support the development and assessment of these skills in individuals. Non-technical skills have been defined as the social, cognitive and personal skills that can complement technical skills and contribute to safe and efficient task performance. This interest has predominately focused on roles within secondary care, with limited research identifying the non-technical skills important to the role of the community pharmacist. This thesis explores the non-technical skills community pharmacists require in order to practise safely and efficiently, how the work system may impact the pharmacists use of these non- technical skills, in addition to documenting the development of a behavioural marker system to describe the non-technical skills of community pharmacists. Method: In order to understand the context in which pharmacists' non-technical skills are enacted, a task analysis of community pharmacy work was carried out using data from documentary analysis, non-participant observations and focus groups. To identify specific non-technical skills relevant to community pharmacy, the findings from a systematic literature review focused on pharmacy practice were combined with data extracted from non-participant observations and semi-structured interviews with community pharmacists. Insights were also extracted from the interviews to explore how elements of the work system impacted on the non-technical skills of community pharmacists. A focus group of community pharmacists organised these data and produced a framework of non-technical skills - the Pharmacists' Non-Technical Skills (PNOTS) behavioural marker system. PNOTS was feasibility tested by a sample of prospective users (i.e., community pharmacists) through the rating of pharmacists' non- technical skills in pre-recorded scenarios. Participants provided feedback on the content, structure, and training of the behavioural marker system in a post-rating survey. Results: This thesis has identified four non-technical skill categories that are important for the role of the pharmacist, forming the highest-level of the PNOTS behavioural marker system, and these are: leadership; task management; situation awareness; and decision-making. Communication was identified as a critical component of the majority of the included skills in the behavioural marker system. Examples of elements included within the framework include delegation, prioritisation, anticipating future statements and the ability to gather information. It was also identified that these skills and elements were impacted by the work system in which the community pharmacy works. Specific themes within each aspect of the work system within the pharmacy were identified, including: the composition of a team, the communication levels between different team members and the existing legislation within the pharmacy that impacted the role of the pharmacist. Conclusions: The non-technical skills that community pharmacists require have been identified, as well as specific themes within the work system highlighted that may impact the performance of the pharmacist with regard to these skills. The developed behavioural marker system, PNOTS, should now be evaluated for its reliability as an assessment tool to evaluate observable behaviours of the pharmacist, in addition to guiding the development of non-technical skills in future, as well as current, pharmacists.