On time delivery with quality and quantity is important for any manufacturing industry, especially in garment sectors. At present, in RMG industries, lead time is decreasing day by day and customer requirements also continuously changing. The primary objective of this study is firstly to identify the defects in sewing sections that hinders the overall productivity of garments industry in Bangladesh and find out the ways how to reduce those defects in sewing line by implementing Just-in-Time (JIT). Three different product lines (Jacket, Polo shirt, and T-shirt) have been considered to implement this study. The sample respondents were selected from a reputed textile industry in Bangladesh. Purposive sampling technique is followed by data collection from sewing section and indication of major problems. After indication, improvement proposal are given to the industry from which the productivity as well as line efficiency has compared before and after applying the technique. The output of the study is that, the production capacity, line target, line efficiency, line performance of the respective sewing section has been increased far well than before within the time duration of three month. It is also suggested that, different techniques like process integration, job sharing, multitasking etc. can also be implemented if responsible authorities of garments industry try to improve the current state situation.