This work, titled An Analysis of the Effects of the Green Supply Chain Management Practices on Firm Performance, aims to contribute to associate, undergraduate and graduate students and sectoral professionals, especially in the fields of International Trade and Logistics. The role of supply chain structures in breaking the linear production processes of products and gaining a circular structure and providing the necessary green transformation is of utmost significance with the European Green Deal studies announced as part of the European Union Climate and Environmental policies. Most of the agreements such as the EU Green Deal and the Kyoto Protocol are based on the concept of Environmental Sustainability, which was first used in the 1970s. This study attempts to examine the effects of green supply chain practices on firm performance under this concept. In the study, analyses were made with the data obtained from 386 companies operating in the organised industrial zones of Gaziantep province as well as the companies included in the ISO 1000 list. We consider this work as a reference source for anyone interested in International Trade, Logistics and Supply Chain uses.