In today’s competitive manufacturing landscape, improving efficiency and reducing waste are critical for maintaining product quality and customer satisfaction. This study investigates the application of Value Stream Mapping (VSM) as a lean manufacturing tool to enhance the testing phase of the product line at a Vietnamese electronics company. Testing, though essential for quality assurance, was found to be a major bottleneck due to manual operations, inconsistent inspection times, and defect-prone procedures. Through a structured VSM approach, the current-state process was mapped, inefficiencies were identified, and a future-state map was designed incorporating automation at key testing stations. The implementation resulted in a 14.3% reduction in cycle time, a 35% decrease in cosmetic defects, and an overall improvement in process cycle efficiency from 11.4% to 16.1%. The case study demonstrates that even in resource-constrained environments, VSM can serve as a powerful standalone strategy to guide operational improvements, reduce production waste, and elevate product quality.