Lean construction is a management philosophy intended to reduce waste and maximize productivity. Despite some examples of 'successful' lean implementation in industry our understanding and interpretation of how the lean concept is diffused within an organization varies. From a cultural perspective the lean construction organization is dichotomously interpreted as either positive and empowering or negative and conflicting scenarios. Both interpretations are representative of end-result cultural awareness. Diffusion theory however, tells us that organizational culture is a dynamic construct, in which culture during implementation processes can be interpreted as positive and negative. Consequently, the adoption of an innovative process such as lean management should be considered as an ongoing implementation process whereby the organizational culture evolves. Diffusion theory assists in explaining how and why organizational cultures mature and evolve as a result of implementation processes. Therefore the aim of this paper is to describe a lean cultural maturity model underpinned by diffusion theory. The purpose of the maturity model is to provide an understanding of organizational cultural awareness associated with the lean phenomenon. The model utilizes cultural and diffusion constructs as a foundation to explore the dynamic nature of culture and how the method of implementation is uniquely diffused within organizations to mature culture.