This paper seeks to explore how age diversity is characterised, understood and managed by HR managers responsible for its implementation. With businesses competing at a global level and demographic trends changing the landscape of the labour market, the diversity approach to managing workplace equality has been heralded as the answer to the political and moral challenges in marrying external competition with internal workplace equality. Nowhere has this been more influential than in recent debates concerning older workers in the labour market, and yet, how age-related HR practices relate to the underpinning philosophies of diversity has not yet been explored in any depth. Drawing from interview data with HR managers from a range of industry backgrounds, this article explores the inherent tensions faced when discussing age as a diversity issue, and the persistent effects of larger social norms related to ageing. By focusing on the concept of difference as a key tenet of diversity, the challenges in ensuring equality while being aware of contradictory messages from both inside and outwith the organisations play a key role in age diversity in practice. This leads to a discussion about the more subtle practices involved in the workplace implementation of age diversity and how awareness of inherent biases may challenge age inequality within organisations.