With the rising attention on the topic of Lean construction and its benefits, more and more companies aim to implement the Lean philosophy in their culture. Together with changing the companies' culture multiple challenges occur. Hence, it is of utmost importance to identify factors, which lead to poor management in Lean construction activities. Therefore, this paper intends to identify and categorize barriers leading to poor implementation of the Lean philosophy. In this respect, a set of barrier groups comprising a total of twenty-seven components were identified. A questionnaire was designed and administered to Lean construction professionals in order to rank the importance level of the selected barriers. The paper proposes that lack of 'top management support', 'misperception about Lean practices', 'lack of information sharing and integrated change control' are the top three barriers for Lean implementation. The findings of the study indicate that Lean implementation might be conducted with higher efficiency and productivity by removing the barriers for implementation. This study might guide Lean professionals to align their strategies with Lean practices by knowing and recognizing the main barriers.