Simple, accurate, precise and sensitive spectrophotometric method for simultaneous estimation of Montelukast (MON) and Levocetirizine (LEV) in combined tablet dosage form have been developed and validated. The ratio derivative spectroscopic method involves measurement of first derivative amplitude of ratio spectra at 250.4 nm for MON and 238.4 nm for LEV as two wavelengths for estimation. Beer's law is obeyed in the concentration range of 4-12 and 2-6 $\mu$g/mL for MON and LEV, respectively. LOD values for MON and LEV are found to be 0.09 $\mu$g/mL and 0.178 $\mu$g/mL, respectively. LOQ values for MON and LEV are found to be 0.277$\mu$g/mL and 0.591 $\mu$g/mL, respectively. The results of analysis have been validated statistically and recovery studies carried out in the range 80-120% to confirm the accuracy of the proposed method.