A Practice Note discussing circumstances under which private employers may have a legal duty to report the criminal activity of employees to law enforcement authorities. This Note examines potential duties to report crimes, including the duty imposed on electronic communications service (ECS) providers to report child pornography crimes, the duty to provide a safe work environment under the Occupational Safety and Health Act (OSH Act), and other state and common law duties. This Note also explains how to avoid direct and vicarious liability by reporting, as well as steps employers can take to minimize the risk of liability for invasion of privacy, defamation, and discrimination claims for reporting employees' crimes. This Note addresses federal law but provides some examples of applicable state laws.