The Green Lean Six Sigma (GLSS) approach represents a robust and integrative methodology for advancing quality and operational efficiency, as well as incorporating green practices to achieve sustainable improvement. This paper proposes a framework suitable for small and medium-sized manufacturing enterprises (SMEs). The framework utilizes the DMAIC cycle of Six Sigma, incorporating tools such as process mapping, cause-and-effect analysis, and Pareto techniques to enhance the quality and focus improvement efforts on the primary sources of inefficiency. Validation was carried out in a small Egyptian sock manufacturing company with limited financial resources to test the effectiveness of the proposed model. Implementation of GLSS initiatives has led to a 70% decrease in defect rates in the considered case, a rise in process sigma level from 1.26 to 1.86, and an increase in daily production by nearly 30%. Green practices were incorporated by minimizing material waste resulting from defective items. Compared to similar small-scale cases, the outcomes are quite satisfactory.