As a renewable biological material that has a myriad of applications, wood has played major roles in human life and history, acting as a shelter, fuel (heating and cooking), food, urban design, heritage objects, and even control on the surrounding environment and atmosphere. Natural forests cannot satisfy the growing needs for industrial timber. Therefore, cultivation of low-density fast-growing tree species has become popular. However, they have drawbacks, like susceptibility to biological degradation. Though these trees can be used for production of wood-based composite panels, the products have themselves weaknesses, such as thickness swelling, and consumption of large quantities of synthetic adhesives. Over the past decades, researchers carried out studies to find modern ways to overcome the above-mentioned drawbacks and weaknesses using nanomaterials and nanotechnology. The present Chapter takes a brief look at the studies focused on protection of wood and wood-based composites against organisms (mainly fungi and insects) and improvement in their biological durability, and limitation of water absorption and thickness swelling.