This paper studies the effects of interfacial friction distribution on the integrity of superplastic formed parts. For that purpose, the deformation of AA5083 superplastic aluminum alloy into a long rectangular box is investigated. The die surface is divided into five regions for local application of friction coefficients. The commercial finite element code, ABAQUSTM , is used to carry out the forming simulations and calculate the thickness distribution, forming time, and forming pressure profile for different combinations of friction coefficients. It is found that friction distribution at the die-sheet interface strongly affects the metal flow during the forming process, which has a direct impact on deformation stability and strain localization. With the proposed optimal variable friction distribution, the quality of the formed parts has been enhanced, while reducing the required forming time.