In today's competitive manufacturing landscape, the sustainability and profitability of enterprises hinge on optimizing production efficiency and reducing industrial waste. ENTER SOLAR GREEN ENERGY exemplifies this challenge, striving to improve its products by identifying and eliminating non-value-added processes. This thesis explores the application of Overall Equipment Effectiveness (OEE) as a diagnostic tool for pinpointing inefficiencies and enhancing productivity within the company. Through a comprehensive study of OEE's theoretical foundations and practical implementation, this research analyzes the performance of ENTER SOLAR GREEN ENERGY's manufacturing processes. Key metrics, such as availability, performance, and quality are scrutinized to uncover sources of inefficiency. The study employs both quantitative and qualitative data collection methods, encompassing statistical analyses and interviews to gather insights.