Now-a-days, natural fiber-reinforced polymer matrix composites have received large attention of the researchers in various applications. The properties of natural fiber composites to a large extent influenced by the type of fibers, treatment method, types of hardener and resin, and fabrication method. In the present study, the hardness behavior of sponge gourd, coir, and jute fiber reinforced thermosetting resin-based composite has been investigated experimentally. Natural fibers were treated with 5% NaOH solution by volume and hand lay-up technique was used to fabricate these composites. The Wt% (weight percentage) ratio of resin and hardener, Wt% of resin & hardener in composite, Wt% ratio of sponge gourd & jute, and Wt% ratio of sponge gourd & coir are considered as control factors which were optimized using Taguchi L9 orthogonal design of experiments. The optimal control factor combination for maximum Brinell hardness was found out and the predicted optimal value, obtained from Taguchi analysis, of Brinell hardness was confirmed by validation experiments. At last, the interactions between control factors or input parameters with Brinell hardness are revealed graphically by interaction plots.