Abstract: The unmodified Iyi-Nsukka kaolinite clay catalyst (UMIKKCat) and thermally modified Iyi-Nsukka kaolinite clay catalyst (TMIKCCat800) were prepared and characterised using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Atomic abrasion spectrophotometry (AAS) to verify catalyst properties. Gmelina seed oil was extracted using Soxhlet extraction method utilising n-hexane as solvent. The percentage oil extracted from gmelina seed was 50%, proven its viability as feedstock for biodiesel production. The extracted lipid was characterised to determine the fatty acid profile using Gas chromatography/ mass spectroscopy (GC/MS) Shimadzu, Japan. The methyl ester produced by transesterification of gmelina seed oil with both catalysts were within acceptable limits of ASTM Standard. Central composite design (CCD) was applied and was found adequate in predicting and optimizing the biodiesel production.