In this research, we explore the impact of international buyer-supplier relationships on sustainability practices in the Ready-Made Garments (RMG) industry, concentrating specifically on the context of Bangladesh. The root of this investigation centers around unpacking the influence of global business interconnectivity on operational approaches at the supplier juncture, with a specific emphasis on sustainability. Two core research queries were set as the guiding posts for this investigation: (1) What is the impact of international buyer-supplier relationships on sustainable practices in the RMG sector of Bangladesh? and (2) How do different types of buyer-supplier relationships influence this impact? Drawing from the theoretical discourse, the study ventured to hypothesize those certain elements of international buyer-supplier relationships - the relational dynamics, enduring alliances, and the commitment of international buyers to sustainability - have a positive bearing on sustainable practices within the Bangladeshi RMG industry. To provide empirical support to these assumptions, a quantitative study involving 66 managers working within Bangladesh's RMG industry was undertaken. Utilizing covariance-based descriptive statistics as our analytical tool, we proceeded to examine the validity of our hypotheses. The findings provided a resounding confirmation, highlighting that attributes like trust, commitment, open communication, and long-term partnerships favorably influence the incorporation of sustainable practices. Moreover, it was observed that the commitment of international buyers to sustainability, demonstrated through the enforcement of standards and initiatives to support suppliers, has a substantial influence on suppliers' operational strategies, elbowing them towards the adoption of sustainable and ethical business practices. These insights shed light on how international buyer-supplier relationships impact global trading dynamics and underscore the intensifying significance of sustainability in modern business ethics. This research extends the theoretical discourse on international business, supply chain management, and sustainability. Additionally, it offers pragmatic insights for managers operating within Bangladesh's RMG industry, accentuating the necessity to cultivate enduring, trust- centric relationships with international buyers and to align their operational strategies with the global shift towards sustainable business practices.