There has been an increasing interest in Lean thinking both in traditional manufacturing/engineering organizations and, more recently, in non-traditional/white-collar settings. Despite the potential benefits, organizations that have implemented lean are facing problems of sustainability. In this study, we examine the nexus between lean thinking and the role of HRM in helping with the sustainability of lean. This paper reports on how recent initiatives may be leading to changes in the ownership of the 'intellectual capital' surrounding lean thinking, new core expertise and the issue of where this expertise should lie. The study is based on 18 interviews with the senior managers responsible for the lean management activity and HR strategy within a dozen large organizations, both in traditional and non-traditional/white-collar organizations. It analyses expert opinions to identify the implicit strategies around lean implementation and generate insights into the spectrum of people-related issues needed for the success of lean and adjustments needed to HR architecture in terms of three core elements: skills and competencies that HR needs; implications for HR practices; and the essential role behaviours that these are intended to create amongst employees. It also examines where expertise and intellectual capital should lie, and identifies the structural solutions being pursued.