The generation of agro-industrial residuesCharacterization, suchBiocomposites as coffee husks, represents an environmental challenge due to their large volume and inadequate disposal. Incorporating these residues into polymerPolymer matrices offers an alternative route to reduce environmental impacts and promote the development of sustainable materials. In this study, polystyrene-based compositesComposites reinforced with coffee husk particles (40–70%) were produced by hot pressing and evaluated through flexural and Charpy impact tests. The results revealed a progressive reduction in flexural strengthFlexural strength and impact resistance with increasing particle content, mainly attributed to weak interfacial adhesion, void formation, and particle agglomeration. Despite these limitations, the use of coffee husk in compositeComposites production demonstrates its potential as a renewable reinforcement, enabling high levels of residue utilization while contributing to strategies aimed at reducing plastic waste and environmental pollution.