This study analyzes thickness-dependent of the yielding behavior and forming limit diagrams (FLDs) of the AA6082-T6 aluminum alloy sheet. Mechanical behavior of the materials of 1 and 1.5 mm sheet thickness is observed having performed anisotropy and tensile tests at 0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, and 90 degrees to the rolling direction. By using Hill-48 and Barlat-89 yield criteria, r-value and yield stress relations were defined and yield loci were obtained. Forming limit diagrams were created using experimental data and Marciniak-Kuczynski (MK) model. It was observed that increased sheet thickness also increases anisotropy while decreasing yield stress; yield locus was found to be smaller. The formability of the material increased as the sheet thickness increases.