This study investigates the potential for enhanced hydrogen production (HP) from the co-fermentation of mixed fruit peels and vegetable waste (MFPVW) with gelatinous solid waste (GSW) as an alkaline supplement and nutrient source. Co-fermentation of mixed fruit peels and vegetable waste with gelatinous solid waste enhances hydrogen production. A series of batch experiments were conducted under thermophilic conditions, evaluating the addition of different GSW concentrations (0–10 g per 100 g of MFPVW) on hydrogen yield. The results revealed that adding 2 g of GSW significantly enhanced hydrogen production and achieved a yield of 94.67 mL H₂/g COD removed, which is a 1.96-fold increase over the control. The optimal GSW concentration not only accelerated microbial activity, drastically shortening the reaction time to 18 hours, but also improved substrate utilization, with 57% COD removal and 53% carbohydrate degradation. These findings suggest that GSW can effectively enhance biohydrogen production from organic wastes, providing a green and efficient solution for producing renewable energy.