Mangifera casturi fructus extract has potential antioxidant activity and potential treatment of various diseases associated with free radicals. This extract has to be formulated in microemulsion dosage form to increase the stability and to help its penetration through human skin. Microemulsion as topical delivery is incorporated in gel base to prolong the local contact to the skin. The purpose of this study was to develop microemulsion based gel formulation for topical delivery of Mangifera casturi fructus extract. Surfactant and co-surfactant concentrations were optimized and pseudoternary diagram was prepared by water titration method. The microemusions were characterized and incorporated with gel polymer to increase the viscosity. The microemulsion based gel was evaluated by its homogeneity, viscosity, pH, adhesion, and spreadability measurement. The results showed that optimum microemulsion formula was contain 1.96%w/w Virgin Coconut Oil as oil base, 15.68%w/w polysorbate 80 as surfactant, and 1.96%w/w sorbitol as co-surfactant. This formula had clear, yellowish color and odorless organoleptic. The average globule size was 4.231±0.308 µm, the type of microemulsion was oil in water, pH value was 7.68±0.07 and the viscosity was 218.75 cPs. The microemulsion was stable with centrifugation test. HPMC as a gel matrix was chosen to construct the microemulsion based gel containing Mangifera casturi fructus extract. The microemulsion based gel showed good physical characteristics and indicate a promising topical delivery of Mangifera casturi fructus Extract. Keywords: Mangifera casturi, microemulsion, gel