The study is directed to questioning the impact of Green Supply Chain Management (GSCM) practices in the organizational performance of one of the dominant sectors of the Bangladesh economy, which is the RMG sector, and it considers this under the scenario emerging with substantial pressure from the international community, finding that the product should come from sustainable sources. The research analyses the relationship between five main GSCM dimensions, i.e., internal environmental management, green purchasing, cooperation with customers, eco-design, and investment recovery by examining their direct impact on affecting the environmental performance as well as their indirect effect on cash and operational performance. Data were gathered from 97 high- and middle-level managers in three ISO 14001 certified apparel companies using a structured questionnaire. Reliability of all the constructions was measured with Cronbach’s alpha (from 0.659 to 0.887), and associations were explored using mean, SD, and multiple regression techniques. The result shows that there is a positive relationship between the overall performance of GSCM and (GSCM in general) organizational performance (β = 0.501, p < 0.001) with an explained variance change of 25.1%. Regarding the overall dimensions of environmental activities, internal environmental management (β = 0.455, p = 0.050) and cooperation with customers (β = 0.411, p = 0.081) have significant relations to both financial and operational performance, respectively. Although the impacts of green purchasing and eco-design are not significant, their inclusion is necessary for sustainable and ongoing development. An important implication of the study is that proper application of GSCM leads to competitiveness, waste minimization, and green responsibility among supply chains.