The purpose of this paper is to measure service quality of the hospital implementing Lean management. This paper assesses patients’ expectation and satisfaction pertaining to hospital service quality. Data collected from 450 patients are analyzed by using the SERVQUAL model. The model compares patients’ perception and expectation of service received across five dimensions of service quality including reliability, responsiveness, assurance, empathy and tangibility. The results of this study reveal that overall service quality score is positive, however, there is no significantly different between overall patients’ perception and expectation. The service quality level of the hospital implementing lean is moderate; the hospital is able to deliver service as expected. In addition, the largest positive gap between patients’ perception and expectation is in term of tangibility. The largest negative gap is with respect to assurance. The findings help the management team to understand areas of improvement. Top management can apply research findings to design and prioritize hospital strategies for improving service quality.