This study explores the use of low-value industrial waste fibres as reinforcement in 3D concrete printing (3DCP) to enhance mechanical performance while promoting sustainability. Traditional synthetic fibres, though effective, pose concerns regarding cost, resource depletion, and recyclability. In contrast, waste fibres from the tapestry, agro-industrial, fishing, and abattoir sectors offer a renewable, cost-effective alternative with mechanical benefits. The research evaluates these fibres’ compatibility with concrete, their mechanical properties, and cost-effectiveness. It examines their effects on the fresh and hardened properties of 3D printed concrete, focusing on tensile strength, ductility, and crack resistance. Using discontinuous fibre reinforcement, the study analyses how fibre content, aspect ratio, and dispersion influence structural performance while maintaining printability and dimensional accuracy. Challenges such as fibre-matrix interactions, water absorption, and dispersion are addressed, along with potential surface treatments and chemical modifications to enhance fibre adhesion and durability in cementitious composites. The experimental methodology involves mechanical testing of fibre-reinforced printed samples to assess flexural strength. The findings demonstrate that incorporating waste fibres has a small impact on flexural performance 3D printed elements. This research provides valuable insights for designers, engineers, and construction professionals aiming to optimize structural integrity and sustainability in 3DCP. Ultimately, it supports the transition to circular and resource-efficient building materials, reinforcing additive manufacturing’s role in sustainable construction.