Behavior-based safety (BBS) methods have been widely reported as an important contributor to the prevention of accidents and improvement of safety performance in construction projects. However, most existing BBS methods fail to look into the impact of the interactions between workers and their supervisors. To overcome this limitation, the impact of supervisor behaviors on safety climate and workers' behavioral performance is examined in this study. A supervisor-focused BBS method is proposed accordingly, which takes group-level safety climate as a mediator to encourage the supervisor behaviors to improve the workers' behavioral performance of construction projects. A case study was carried out in a construction project in Hong Kong. The statistical analysis proved that the intervention with supervisor behaviors resulted in significant improvement in the safety climate, the workers' behavioral safety performance, and the sustainability of the BBS impacts. The results demonstrated that focusing on supervisor behaviors is a viable approach for ameliorating the effectiveness and sustainability of BBS in improving the safety performance in the construction industry. (C) 2017 American Society of Civil Engineers.