The purpose of this study is to optimize the composition of extragranular excipients (EGE) and mixing time of granules with EGE of paracetamol tablet formulation using Design of Experiments (DoE) approach. The effect of the composition of EGE and the mixing time of granules with EGE on granule and tableting properties of paracetamol tablet formulation was investigated using a combined model of mixture and process factors (Design-Expert 12). A total of 18 tablet formulations were manufactured by wet granulation using varying compositions of EGE and varying mixing time. Granule and tablet properties of each formulation were evaluated as response variables for the design, data generated were fitted into models and analysed to generate a design space that was used for optimization studies. The proposed EGE composition as predicted by the design was confirmed and validated after preparation and evaluation of the granule and tablet properties. The optimized composition for the EGE that yielded granules and tablets of desirable characteristics was found to be maize starch (5 %), talc (4.9 %) and magnesium stearate (0.1 %) with a mixing time of 2 min. The tablets produced with the optimized composition had better mechanical strength and disintegration time than the formulation prepared using an existing formula of maize starch (7.8 %), talc (2 %) and magnesium stearate (0.2 %) that were obtained using the One Variable at a Time (OVAT) approach. This study confirmed the relevance of quality by design in development of pharmaceutical formulations.