Naproxen is an NSAID used to treat inflammatory joint conditions including osteoarthritis. In this study, we set out to create a novel microemulsion formulation for transdermal administration of Naproxen. To choose excipients with excellent drug loading capacity, solubility of drug in different oils, surfactant, and co-surfactant was assessed in pre formulation tests. Capmul MCM C8 was chosen as the oil in the microemulsion's formulation, while labrasol and ethanol were chosen as the surfactant and co-surfactant, respectively. The concentrations of the oil phase, Smix, and distilled water used in the preparation of the Naproxen microemulsion were calculated using pseudo ternary phase diagrams. Three tests-a centrifugation tests, a heating and cooling cycle test, and a freeze thaw cycle test—were used to determine the optimal formulation. The % transmittance, droplet size, and cloud point of the optimized formulations were also measured. Because of its high % transmittance, the MF2 formulation stands out as the best of the bunch. A minimum globule size of 35.2 nm was observed for MF-2. The zeta potential of MF2 was calculated to be +19.0mV. Compared to previous batches, the MF2 formulation demonstrated faster drug release during the in vitro diffusion test, with peak drug concentrations occurring between 4 and 8 hours after the test began.