According to Pearson's hard/soft (Lewis) acids/bases concept, sulfur compounds in diesel will prefer to interact with intermediate or soft Lewis acid sites since they are soft to intermediate bases. In this work, intermediate Lewis metal oxides (MO) acids were loaded on activated carbon (AC) and alumina (Al2O3) to desulfurize diesel using adsorption. For carbon-loaded MO, NiO showed the highest desulfurization activity of 89% and 50% when using both model diesel and conventional diesel, respectively. The activity of Al2O3 and Al2O3 supported MO was approximately four times less than that of AC for model diesel desulphurization. It is suggested that the low activity of Al2O3 is due to lower surface area, pore distribution, and the strong acidity nature of Al2O3 since the adsorbates are soft to intermediate Lewis bases. Lower activity, 2-4 times, was observed when treating conventional diesel compared to model diesel. This lower activity is due to competitive adsorption with compounds such as naphthalene and indole. Despite this difference, the activity trends were generally maintained suggesting that the use of model diesel is not a bad technique for screening adsorbents. Selectivity on AC was observed to decrease in this order: 4-MDBT > 1,4,6-TMDBT > 4,6-DMDBTZ similar to 4E,6-MDBT similar to 2,4,6-TMDBT. This suggests that steric hindrances dominate selectivity for these high-molecular weight molecules. Finally, it was observed that the challenge with regeneration of adsorbent (AC) that treated conventional diesel using solvent extraction is competitive desorption of hydrocarbons and sulfur compounds.