This study examines the synergy of zeolite-bentonite catalysts in thermal distillation of waste lubricant oil for alternative fuel production. Zeolite was modified with NH₄NO₃ and calcined at 500 °C to increase acidity, while bentonite was activated with HCl and calcined to improve surface area and thermal stability. Distillation was performed up to 400 °C using zeolite: bentonite ratios of 1:1, 2:1, and 1:2, and compared with a non-catalytic process. XRD and SEM-EDX characterization revealed changes in crystal structure, surface morphology, and elemental composition that supported higher catalytic activity. The mixed catalyst reduced viscosity and density while increasing calorific value. The 2:1 ratio produced the highest calorific value, 6509.46 cal/g, whereas the 1:1 ratio most effectively lowered initiation temperature and time from 298 °C and 34 minutes to 229 °C and 26 minutes. Overall, this catalyst synergy improves distillation performance and liquid-fuel quality from waste oil conversion.