In this paper, evaluation of base materials and manufacturing environmental sustainability of selected branded T-shirt products made by Bangladesh is presented. The study is based on performing various eco-friendliness tests for the product base materials and evaluation though a standard tool named Higg Index. For this study, selected apparel branded T-shirt products from renowned brand, namely B, C, D, E, and F, and a researcher-developed BUTex-Innovation brand A are taken into consideration. Better environmental sustainability results, i.e., higher score, is obtained by A, B, C, and D branded T-shirts, but local branded product of E and F resulted in poor environmental sustainability with lower scores in terms of product eco-friendliness tests and High Index assessment tool. Besides, many weaknesses and opportunities for improvement of environmental sustainability in materials and manufacturing stages are identified and suggested to lead the textiles and clothing sectors towards sustainable growth.