Environmentally friendly heterogeneous sol-gel La2O3-Al2O3 materials with no alkaline or alkaline-earth metals were synthesized to be used as catalysts for biodiesel production by a transesterification reaction of canola oil. The effect of the La2O3 content (0, 3, 5, 7, and 10 wt%) on the catalytic performance of the La2O3-Al2O3 mixed oxides, as well as the textural, structural, and surface properties, is reported. It was found that La2O3 loading increases the number and strength of basic sites up to 7% La2O3-Al2O3 catalyst with an La2O3 monolayer formation with 0.23 mmol highly dispersed La atoms over Al2O3 is reported. A correlation between catalytic performance, informed as biodiesel production with basicity, carbonation degree, and La2O3 dispersion is obtained. The extent of biodiesel production (45% at 65 A degrees C and 5 h of reaction time), under mild reactions conditions, for the monolayer La2O3 alumina catalyst is the highest reported up now for nontoxic heterogeneous catalysts.