This paper describes the research, analysis and development of a model clarifying the similarities and differences in competencies and personality factors1 associated with effective Leadership and Management in the Royal Navy. A questionnaire study was conducted on a sample of 261 Officers and Ratings (Sailors). Their performance was rated through the organization's rigorous appraisal process, whilst competency and personality data were gathered through the Occupational Personality Questionnaire and the Leadership Dimensions Questionnaire. The results identify the common and unique relevance of specific competencies and personality factors and so provide an illuminating insight into the differences between the constructs of leadership and management. The critical factors related to effective leadership and management performance are also identified.