This thesis investigated influences on primary school deputy-principals’ motivations to apply for principalship in the early twenty-first century in the Irish Republic. This required the exploration of both principals’ and deputy-principals’ roles in management and leadership to discover how better to prepare deputies to continue to the principalship. The research approach sat firmly within the qualitative paradigm, using semi-structured interviews with twelve primary deputy-principals exploring their construction of deputyship and principalship from their professional socialisation experiences. Findings revealed the complex relationship which exists between both roles and the extent to which the pervading school culture determines how much meaningful leadership opportunity is distributed beyond the principal. A major outcome of the study is a constructed knowledge of the nature and culture of Irish primary deputyship. Three new typologies of deputy-principalship provide a new perspective on the deputyship role, concluding that the gap in experiences and knowledge between deputyship and principalship is so great that energy should flow into the formation of formal, planned and structured preparation for a deputyship transition into principalship