Tensile properties of A 6061-T6 aluminum alloy friction stir (FS) welds were characterized using a digital image correlation (DIC) method. The FS welds were fabricated under three different sets of welding conditions. The tensile stress-strain relations for the weld zone of the FS welds were determined with a testing machine equipped with an extensometer. The DIC method was applied to simultaneously measure full-field strain distributions over the gage length of FS weld tensile specimens during loading. The strains within the gage length of the FS weld specimens were also determined by superimposing respective local strains measured with the DIC method using "the rule of mixture''. The DIC measurements show that the local strains in the FS weld specimens concentrate significantly at the boundaries between a stir zone (SZ) and a heat affected zone (TMAZ) with increasing tensile load. The tensile stress-strain curves for the respective local areas were modeled by Ludwik equation. The predicted tensile stress-strain curves within the gage length were compared with the experimental ones obtained using the extensometer. Some discrepancies are found between both tensile stress-strain curves in a smaller strain range. The main reason for this is due to the DIC measurement errors involved in the displacements in the smaller strain range.