Environmental Management Accounting (EMA) is increasingly recognized as a vital internal tool for improving corporate environmental performance. This paper examines the hypothesis of the existence and degree of the impact of EMA on environmental performance (EP) in the Bangladesh ready-made garment (RMG) industry, the mediating factor is resource efficiency performance (REP), and the moderating boundary condition is good governance (GG). Based on the resource-based theory, dynamic capability theory, and institutional theory, the moderated mediation model is examined using partial least squares structural equation modeling (PLS-SEM) and survey data collected from 331 managers at medium- and large-scale RMG manufacturers. The findings confirm that EMA has a significant positive effect on EP, either directly or indirectly through REP, with REP accounting for about 47 percent of the overall effect. Good governance has a significant, albeit weakening, moderating effect on the EMA-REP pathway: in high-governance contexts, external regulatory pressures seem to partially replace internal EMA systems, thereby promoting resource efficiency. The results add to the literature on environmental accounting by explaining a process-based, governance-mechanism-contingent mechanism through which EMA affects environmental performance and by offering practical advice to managers and policymakers in the context of developing-economy manufacturing.