Traditional formwork design processes entail considerable waste, increasing non-value-adding manpower costs and operational time. The purpose of this research is to use lean thinking in formwork design so as to enhance design correctness and eliminate waste through establishing a Lean Formwork Design Process. In the design process, the concurrent design concept is adopted to provide a visual communication platform for design team members using Building Information Modeling (BIM). Industry Foundation Classes (IFC) are used as a protocol for sharing design artifacts. Design correctness is established to review and correct design errors, thus allowing for the construction of an organizational learning environment. Finally, the Lean Formwork Design Process is conceptualized using stock-flow diagrams. A real case is used to validate the applicability of the proposed approach. Application results show that the proposed method can enhance design correctness and reduce manpower waste and operational time in formwork engineering. This study is one of the first to apply lean thinking to improve practices in formwork design.