Building materials emit 250 million tons of CO2 annually, aggravating environmental impacts. Natural fiberboards offer a sustainable alternative. 100% coriander-based fiberboards are promising due to their lack of formaldehyde emissions. After harvest, coriander fruits undergo thermo-mechanical pressing and solvent extraction to extract vegetable oil. The resulting press cake is then mixed with extrusion-refined coriander straw, and thermopressed to obtain the coriander boards, proteins from the cake acting as a natural binder. A preliminary study optimized the hot pressing, and conditions to achieve flexural properties comparable to commercial medium density fiberboard (MDF) were identified. The present study compares the environmental performance of coriander fiberboard with commercial MDF using an attributional life cycle assessment. The functional unit is defined as the production of 1 m2 of coriander fiberboard, intended for use as a partition wall, following a cradle-to-gate approach in France. Data collection was based on experimental studies conducted at TRL 5 to 6. Results show that producing the MDF-like board from coriander has a greater advantage in terms of reducing CO₂ emissions compared to the production of conventional MDF. Furthermore, the cultivation and harvesting stage of coriander was identified as the primary contributor to pollution across several impact categories.