ABSTRACT We investigate the effect that adherence to the Institute of Internal Auditors’ Core Principles has on mission-based internal audit (IA) characteristics. Using 255 survey responses from Chief Audit Executives in Germany, Switzerland, and Austria, we find that adherence to the Core Principles is associated with a greater scope of IA work, alignment with the strategic goals of the organization, usage of IA work product by a greater number of stakeholders, and a greater extent of IA work product usage by those stakeholders. We find that only three of the Core Principles are associated with at least one of these characteristics and that no Core Principle is dominant in explaining all characteristics. Our results expand upon the fledgling academic literature on the globally mandated Core Principles, add to the existing literature on IA quality, and support practitioner adoption of the Core Principles as a means of achieving IA effectiveness. Data Availability: Please contact the authors. This project was sponsored by a national IIA chapter. JEL Classifications: M40; M42; G34; M4; G3.