This paper investigates the barriers that hinder the implementation of lean manufacturing in wood and furniture industries as the adoption of this philosophy in such industries is not promising especially in emerging economies. To this end, a comprehensive review of the literature was performed to identify the barriers and develop a conceptual model. Next, structural equation modeling is employed to examine the model using the collected data from 131 wood and furniture companies. The findings revealed a synergetic effect between three key factors—culture and human attitude, knowledge, and resources—which play a crucial role in implementing lean. The analyses indicated the reasons of companies refused or not ready to implement lean on knowledge and culture and human attitudinal issues, particularly in companies that have limited resources. It is believed that resource issues are an obstacle to lean implementation, but not as important as knowledge and culture and human attitudinal issues. Sufficient knowledge is needed to deploy lean practices as well as changes in culture and human attitude. Investigating the relationships between these three key barriers is a contribution that this study intends to become a forward step for promoting lean manufacturing among under-studied industries. This paper also proposes that through adopting the activities for lean implementation, small and medium enterprises can experience and quantify the positive impacts of lean practices. Government agencies, universities, and professional bodies can support such enterprises in this transition through targeted interventions that address the barriers presented.