There is a dearth in knowledge on artisanal tannery wastewater treatment as most studies are focused on treatment of wastewater generated from modern-day leather manufacturing industries. The extensive use of plant materials in artisanal tanneries introduces high loads of polyphenolic compounds in the wastewater rendering biological treatment of the wastewater ineffective. This study, therefore, employed coagulation-flocculation process to pre-treat artisanal tannery wastewater with the aim of applying the central composite design, a statistical approach in Response Surface Methodology (RSM) to model and optimize the removal of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS) and turbidity and to minimize Sludge Volume Index (SVI). Optimization process focused on the two most important influencing parameters: dosage of aluminium sulphate and initial pH of wastewater. Results revealed that optimal pH and aluminium sulphate dosage of 6.09 and 11.6g/L respectively could yield maximum removal efficiencies of 38.51% of COD, 76.05% of TSS and 79.64% of turbidity from the wastewater with a minimum SVI of 29.57mL/g. Further experiments conducted to validate these results showed a good agreement between the experimental and predicted results signifying the suitability of RSM for optimization of the coagulation treatment process. This is the first reported study on optimization of coagulation-flocculation treatment of artisanal tannery wastewater. Results of this study can be used practically for efficient pre-treatment of artisanal tannery wastewater.