The Joint Commission issues sentinel event alerts to highlight commonly reported, novel, or previously unrecognized safety concerns and make recommendations for how to address these critical safety issues. This alert emphasizes the link between leadership and a positive safety culture. Leaders can model a nonpunitive approach to error reporting and investigation, and they should ensure that unprofessional or intimidating behavior is not tolerated. The alert recommends periodic measurement of safety culture using a validated tool such as the AHRQ Hospital Survey on Patient Safety Culture or the Safety Attitudes Questionnaire. Safety assessments should then be used to inform team training and quality improvement efforts. A past PSNet perspective discussed the role of leadership in patient safety. This alert was originally published in 2017 and updated in 2021.