This study assesses the impact of ISO/IEC 17025 accreditation on quality performance, operational efficiency, and customer satisfaction at Eskom’s Flow Laboratory, a key calibration facility in South Africa’s power generation sector. It investigates how ac-creditation has influenced technical competence, service delivery, and customer con-fidence. Data was collected through questionnaires from 82 customers across sectors including power generation (28%), environmental testing (24%), manufacturing (20%), mining (15%), and other industries (13%). Results show strong positive perceptions of post-accreditation performance, with an overall satisfaction mean of 4.55/5 and 88% agreement among respondents. The highest scores were for result accuracy and relia-bility (4.7), staff competence (4.6), and customer willingness to recommend the lab (4.8). Furthermore, 91% agreed that accreditation improved confidence in test results, while 88% cited stronger quality control and traceability. Reported benefits included enhanced efficiency (85%), transparency (83%), and international recognition (87%). Overall, ISO/IEC 17025 accreditation has significantly strengthened the laboratory’s technical credibility, operational consistency, and client trust. The study concludes that sustaining these gains will require ongoing investment in staff development, customer engagement, and technology, in support of Eskom’s broader goals of operational ex-cellence, reliability, and customer satisfaction.