This study used ternary substrates consisting of honne, neem, and yellow oleander (HONOYO) oil blend to produce methyl-esters for sustainability of raw materials for biodiesel synthesis. A biomass-based catalyst from calcined mixed agro-wastes consisting of kolanut pod, cocoa pod, and plantain peel ash was employed to transesterify the blend. A two-step method was adopted to convert HONOYO into methyl-esters. Taguchi L9 experimental design tool was used to ascertain the interactive effects of microwave irradiation power (W), Methanol/oil ratio (MeOH), time (min), and agro-wastes synthesized catalyst ASC (wt %) on the yield of methyl-esters from HONOYO. Results demonstrated that at 3:1 MeOH, microwave power of 150 W, ASC of 1.5 wt %, and reaction time of 1 minute, a yield of 80.96 % was achieved. HONOYOB satisfied ASTM D6751 and EN 14214 standards. Performance evaluation of the process input variables suggests weight of ASC as the most significant process parameters for HONOYOB yield. This work authenticates that biomass catalyst from agricultural wastes can adequately be applied to synthesis biodiesel effectively from blends of non-edible oils to supplement fossil diesel.