Mefenamic acid (MA) is a BCS II class NSAID drug. It is available only in the form of tablets, capsules, and pediatric suspensions. Oral administration of MA is associated with severe gastrointestinal side effects. The aim of this study was to develop a convenient and low-cost transdermal drug delivery system for MA using proniosome as a novel carrier without the addition of penetration enhancers. The formulation factors, such as the presence of cholesterol, types of lecithin, and surfactants were investigated for their influence on the entrapment efficiency, rate of hydration, vesicle size, and zeta potential, in vitro drug release and skin permeation in order to optimize the proniosomal formulations with the minimum dose of the drug. Furthermore, the in vivo anti-inflammatory effect was evaluated on a formalin-induced rat paw edema model. The results showed that the type of surfactants had higher impact on the entrapment efficiency than the type of lecithins, with the highest in Span 80 (82.84%). The release of MA from Span 80 proniosomal gel was significantly affected by the type of lecithin used. The addition of cholesterol significantly increased both the drug release and the skin permeation flux of MA. Zeta potential showed a stable A4 noisomal suspension. DSC revealed the molecular dispersion of MA into the loaded proniosomes. In vivo study of the treatment group with MA proniosome gel showed a significant inhibition of rat paw edema compared with the same gel without the drug (control). The results of this study suggest that proniosomes are promising nano vesicular carriers and safe alternatives to enhance the transdermal delivery of MA.