The ever-growing world population demands material consumption and drives material discovery. The progress of modern society accompanies the advent of advanced materials to enable new performance and functionalities, as epitomized by the invention of two most representative man-made materials: steels (4000 years ago) and petroleum-derived plastics (~80 years ago). The widespread use of steels (and other alloys) and plastics as structural and functional materials has radically revolutionized our daily life, which, however, also comes with heavy environmental impacts. The tremendous energy/water cost and carbon footprint of manufacturing steels and the ever-devastating global white pollution due to plastic waste pose grand challenges to the sustainable future of humankind. Aiming to address such grand challenges, we have been working on developing advanced sustainable materials that hold the promise to replace steels (and alloys) and plastics in recent years. To this end, we focus particularly on cellulose, the most abundant biopolymer on Earth, as the source of sustainable materials. In this talk, I will showcase a few examples of advanced sustainable materials developed at the Laboratory for Advance Sustainable Materials and Technology at UMD, including transparent strong and tough cellulose nanopaper to replace plastic foils; superwood as a potential structural material to replace steels and alloys; cellulose-based composites to replace petroleum-derived plastic straws and packaging foam, etc. These high-performance, low-cost, and nature-based advanced materials offer an array of promising material solutions toward a sustainable future.