The Amazon Region (AR), with its vast biodiversity and rich natural resources, presents a unique opportunity for the development of sustainable polymer composites (PCs) reinforced with residues from both timber and agro-extractivism industries. This study explores the potential of Amazonian residues, such as sawdust, wood shavings, and agro-industrial by-products such as açaí seeds and Brazil nut shells, to enhance the mechanical, thermal, and environmental properties of polymer composites. By integrating these natural materials into polymer matrices, significant improvements in the composite performance were achieved, including increased tensile strength, thermal stability, and biodegradability. The study also highlights the environmental and economic benefits of using these residues, promoting waste reduction and supporting a circular economy in the region. Through case studies and detailed analyses, this study demonstrates the feasibility and advantages of incorporating Amazonian residues into composites for a wide range of applications, from construction materials to consumer goods. This approach not only adds value to the by-products of Amazonian industries, but also contributes to the global effort toward sustainable material development.