Although lean methods have been used on construction projects for over three decades, the adoption of such methods into the project delivery process varies in formal planning and implementation. This makes it challenging to benchmark the performance of projects implementing lean construction methods. Preliminary analysis of literature combined with a content analysis of expert interviews with lean practitioners suggested that there is an opportunity to improve the awareness, understanding, and education of lean methods. As a result, the adoption of lean methods would also improve. However, to improve the awareness, understanding, and education of lean methods, there is also the need to develop consistent terminology that can be used. Having identified this need, further investigation of various knowledge representation techniques resulted in the identification of domain ontologies as a mechanism to organize the domain of lean construction methods. This paper presents the summary of the various approaches and tasks adopted from ontological methodologies to outline the process for developing the lean construction methods ontology and the ontology structure. The paper concludes with future research directions focused on documentation of the knowledge within the ontology, ontology evaluation using expert interviews, and ontology application using project case studies.