In this research, the impact on and relationship of Authentic Leadership with Leader Accountability was investigated. This mixed methods study was conducted within UK non-profit organisations. This investigation had two strands to its key objective; the first was to note the impact of the two theories using Quantitative measures of the Authentic Leadership Questionnaire and Leader Accountability Scale. The results of this phase of the research supported the propositions that the independent variables (self-awareness, balanced processing, relational transparency, internalised moral perspective) of Authentic Leadership positively impacted on the dependent variables (responsibility, openness, answerability) of Leader Accountability. The second was to understand the relationship of the two theories using a Qualitative approach which adopted semi-structured interviews and cross-case analysis. The findings of these interviews with non-profit leaders and followers revealed that the perceptions of authenticity and accountability are evident; those leaders who exhibited these virtues were praised by followers as being effective leaders. Therefore, in general, Leader Accountability can be regarded as an actionable strategy to further support Authentic Leadership behaviours within the UK non-profit sector. Contributions to academic knowledge are that for the first time, the theory of Authentic Leadership was studied in relation to Leader Accountability within the non-profit context. Both the theories were investigated using mixed methodology, and self-awareness was found to be the main leadership characteristic apparent within the UK non-profit sector along with other variables of authentic leadership and leader accountability. The implications and future recommendations are also addressed.