Self-condensation of biomass-derived methyl ketones catalyzed by solid bases or acids produces corresponding cyclic trimers exclusively in excellent yields. Condensates containing 24-45 carbon atoms are shown to be suitable lubricant base-oils after the removal of residual unsaturation and oxygen. Properties of cycloalkanes produced from biomass are very similar to those of conventional lubricant base-oils. The process reported here offers an environmentally benign alternative to the current non-selective production of lubricant base-oils from α-olefins, and avoids the production of corrosive waste products.