The need of plant based insecticides is increasing day by day because of resistance acquired by lepidopteran pests against synthetic pesticides. Considering this, larvicidal activity was tested with leaf extracts of Zanthoxylum armatum extracted with hexane and methanol against 3rd, 4th and 5th larval instars of Spodoptera litura. The plant extracts were prepared by maceration technique. The concentration of methanolic extract was 735.09g/L while that of hexane extract was 806.45g/L. Mortality rates were assessed on the basis of knock down toxicity i.e., KD0, KD50 and KD100. Results demonstrated that KD100 for 5th larval instars was 7+0.5 days for both hexane and methanol extracts of Z. armatum. Greater larvicidal effects against 4th larval instars were shown by methanolic extracts where KD50 was recorded to be only 3 days. The study reports that the leaf extracts from Z. armatum can be a potential source of bio- pesticide against S. litura.