This course provides an in-depth study of the principles and practices of quality auditing within ISO 9000-based Quality Management Systems (QMS) across supply chain, manufactur- ing, and service operations. Students learn to plan, conduct, re- port, and follow up on internal, supplier, and logistics-partner audits using the process approach and risk-based thinking de- fined in ISO 9001 and ISO 19011. The course also introduces sector-specific QMS extensions, such as AS9100 for aero- space/defense and ISO 13485 for medical devices, to illustrate how audit requirements evolve in safety-critical industries. Emphasis is placed on auditing supplier processes, evaluating upstream and downstream performance, and verifying correc- tive actions that strengthen end-to-end reliability, customer satisfaction, and organizational compliance. math skills are required.