To fulfill the consumer expectation, cosmetic industries mostly add glycolic acid aswhitening agent to the sunscreen preparation. The aim of this research was to knowthe effect of glycolic acid addition with the concentration of 8, 10, and 12% w/w onphysical stability and effectiveness of sunscreen product containing oxybenzoneand octyl methoxycinnamate (2: 7% w/w) in carbomer 940 gel. The physical stabilitytest was done by observing physical appearance, pH, and spreading ability during 60day storages on zone IV condition (temperature 30±0.5° and RH 70±2%). The efficacywas determinated base on SPF (Sun Protection Factor) value by spectrophotometer.The result of the physical stability test showed that glycolic acid additionaffects the physical appearance (consistency) of sunscreen product, but pH and spreadingability are relatively stable. The efficacy test result showed that the addition ofglycolic acid has an effect on SPF value of sunscreen product. Product which combinedwith glycolic acid showed a significant increase of SPF value, compared tocontrol formula. The addition of glycolic acid increased SPF value and alter theeffectiveness category from extra protection to maximal protection.