In this study, the performance of a bench scale aerobic sequencing batch reactor (SBR) was investigated for the treatment of tannery wastewater. Mixed culture obtained from the activated sludge process treating tannery wastewater was used in the reactor. SBR was operated at different operating conditions by changing the hydraulic retention time (HRT- 5 – 2 days) and initial substrate concentration (6240mgCOD/L, 4680 mgCOD/L, 3220 mgCOD/L and 1560 mgCOD/L). From the results it was found that a maximum reduction in COD and colour were found to be 79% and 51% respectively. In this study, first order and diffusional models are used to describe the kinetics of the degradation of tannery wastewater in SBR. The model parameters were calculated. From the R2 value calculated the first order model fits the data well.