A lean six sigma has been a useful tool in improving production yield, services, and other business problems however when use on capacity improvement it is not yet defined. This paper is a case study on the implementation of lean six sigma on capacity improvement as an advanced [what? method, process etc.?] in manufacturing plants. This case study capitalizes on the data collected in an advanced manufacturing factory. As such, different methods of data analysis are required for the more given data such as Analytical Hierarchy Process (AHP). AHP was able to list the possible options in improving capacity as well as the impact of each option on the overall weekly output of the production line. As highlighted by AHP, improvement of machine cycle-time is the top option that gives the most impact on increasing weekly output. Root-cause analysis is used to dig deeper into the root cause of each factor identified from AHP. Thorough bottleneck identification using blueprint diagrams is carried out. Through the implementation of the DMAIC method, the capacity improves and the effectiveness of lean six sigma on capacity improvement was verified.