Wood is a natural and renewable resource whose use has recently increased in fields such as civil construction, fiber production, and biopolymer development. Thanks to its hierarchical structure at different levels, wood can be utilized in new applications with the assistance of Polymer Science. At the macroscale, the use of adhesives, primers, and special physicochemical treatments for durability improves the quality of engineered wood products; at the microscale, thanks to its anisotropic and porous structure, filters, insulators, sensors, and actuators are produced for water purification, thermal insulation, and smart materials; and at the nanoscale, new biopolymers and nanoparticles are synthesized for the development of adhesives, fibers, films, foams, and composites. This makes Wood Materials Science a field where physicists, chemists, and engineers combine their knowledge to achieve more sustainable products and innovative applications.