In the present study, a series of 12-hydroxystearic acid derivatives (HSA), namely compounds 1–5, were synthesized as potential low-molecular mass gelators. They were designed to have similar molecular structures with different alkyl chain lengths, in order to investigate the effect of the alkyl chain lengths in HSA-modified molecular structures on thermal stabilities and supramolecular structures of the organogels. All compounds 1–5 could form stable organogels in several organic solvents. Especially, compounds 2 and 3 showed excellent gelation ability, and their minimum gelation concentrations in m-xylene solvent were 2 mg mL–1. The thermal stability and morphological studies showed that the alkyl chain lengths had an important influence on the supramolecular organogels. Moreover, Fourier transform-infrared (FT-IR) technology and X-ray diffraction (XRD) characterization were employed to study the main driving forces and molecular packing patterns of gelators in the gel phases. Eventually, the formation mechanism of the organogel was proposed.