<b>Composite materials, which can have a wide range of properties, can have an important role in protecting the natural environment. Until now, the most popular fibres used in composites have been those obtained by chemical processes. Natural fibres are much less commonly used, but interest in them is growing due to the principles of eco-development, care for the environment, and their important fact that they are biodegradable. Sheep wool, due to its unique physicochemical properties, such as thermal and sound insulation and the ability to absorb and release moisture, can be used as a fibre in biodegradable composites. Biodegradable polymers are becoming increasingly popular as an alternative to plastics, which have a negative impact on the environment. Although the use of biodegradable polymers is limited by their poor mechanical and thermal properties, a filler in the form of sheep wool fibres increases the mechanical properties of the composite and reduces production costs, while maintaining its biodegradability. Mixed wool is treated as a waste product which is difficult to utilize in the textile industry, but innovative applications in agriculture and medicine provide the opportunity to make use of it. As a fibre with unique physicochemical properties, wool can be used as an element of biocomposites in line with the strategies of bioeconomy and sustainable development.