This thesis project proposes the introduction of bio-based materials in the design of unitised curtain wall façade systems. The work investigates a circular bio-based unitised façade design to understand its feasibility regarding thermal, technical, and environmental performance. The research is divided in four phases, including the material, system design, performance, and environmental assessment level. The material phase serves as a literature review to study the current technologies and available bioproducts in the market to make an informed selection. Once the materials are selected, the system design phase starts with an emphasis on dynamic construction and design for disassembly features. Overall, this study aims to minimize reliance on non-renewable resources such as aluminium in façade systems. Therefore, it is important to analyse the thermal and hygrothermal behaviour of the materials to integrate design characteristics that can improve their performance while protecting their structural integrity. After the feasibility of the design concepts gets validated, a comparative environmental assessment against standard aluminium façade systems is conducted to quantify the sustainability impact of the proposed system. Ultimately, the research project proposes a detailed exploration into the feasibility of circular, bio- based unitised façade systems. Therefore, the introduction of bio-based systems that support sustainable methodologies and practices from the material, design, and system level is demonstrated.