The apparel industry in Bangladesh plays a vital role in the country's economic growth and exports. To improve productivity and meet new challenges, operational performance must be optimized and resources utilized efficiently. The study aims to improve and optimize Overall Equipment Effectiveness (OEE), a tool that can help manufacturing industries develop processes ensuring quality, consistency, and productivity while minimizing significant losses. Data was collected from an apparel company and its existing OEE factors - availability, performance, and quality - were found to be below world standards. Key improvement factors were identified through analysis. A simulation model showed output could be improved by 8.87% by focusing on key factors. Design of experiments optimization identified the most influential factors and their relationship to OEE.