Abstract—Ultra-high precision machining (UHPM) is the most suitable manufacturing process for the production of various optical components with high precision requirements and minimal defects in the superficial surface layer from various materials. To get the desired surface finish and dimensional accuracy, single-point diamond turning (SPDT) is preferable. This study is therefore aimed at determining the effects of three (3) machining parameters (cutting speed, feed rate and depth of cut) on the surface finish generated on single-crystal silicon (SCSi) workpiece. Series of diamond turning operations were performed sequentially with 1.5 mm nose radius, –25o rake angle, 10o clearance angle and 1–4o side cutting edge angle SPD tools on a Precitech Nanoform 250 ultra-grind lathe machine based on Box-Behnken Design in Response Surface Methodology by varying the three (3) cutting parameters. Analysis of variance was used to determine the influence of each of the machining parameters and their interactions on the response. The results revealed that feed rate is the most influential factor affecting the surface finish followed by cutting speed. Depth of cut was found to have the least influence on the response. Statistical analysis was used to ascertain the accuracy, adequacy and reliability of the developed model.