CaO derived from calcined eggshell was doped with Na-K by wet impregnation method and the effect of different Na/K molar ratios was investigated on biodiesel production from canola oil. The catalysts were characterized by X-ray Powder Diffraction (XRD), Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and Thermogravimetric (TGA) analyses. FAME yields were determined by Gas Chromatography-Mass Spectrometry (GC-MS). The Na-K/CaO catalyst with Na/ K molar ratio of 1 showed the highest FAME yield of 97.6% at optimum reaction conditions. Structural investigation of materials revealed that FAME yield was proportional to the number of basic sites on the surface of catalyst. The optimum reaction conditions were found to be catalyst loading of 3 wt%, methanol to oil molar ratio of 9:1, reaction temperature of 50 degrees C, and reaction time of 3 h. (C) 2020 Elsevier Ltd. All rights reserved.