Recycled Fibres in 3D printing offer better mechanical performance and help the environment. In this work, a literature review is carried out to evaluate the materials used, mechanical performance, and environmental ben0efits associated with recycled fibre-reinforced composites in 3DP. From the overall search, it was found that polypropylene fibres are the most commonly used recycled fibres in 3DP. When combined with other fibres, recycled polypropylene fibres show a 38–77% increase in tensile strength. Additionally, using recycled continuous metallic fibres in acrylonitrile butadiene styrene plastic improves Young’s modulus by around 51% and tensile strength by 18–19%. In 3D concrete printing, adding recycled polyvinyl alcohol fibres results in a 41% increase in compressive strength and a 74–82% improvement in flexural strength compared to mixes without fibre. From an environmental perspective, recycled polyethylene terephthalate and high-density polyethylene composites help reduce waste and significantly lower emissions. These materials can cut carbon emissions by 70–75% and use 80–90% less energy than virgin materials. The performance of recycled fibre composites depends on the type of fibre, matrix material, and processing conditions.