Production of diglycerides (DG) plays an important role in food, pharmaceutical, and cosmetic industries. In this study, optimal conditions for DG synthesis via noncatalyzed esterification of oleic acid with glycerol were determined. The temperatures (150°C, 175°C, and 200°C), oleic acid to glycerol molar ratios (1:1, 2:1, 3:1, and 4:1), and initial water content were varied to determine DG selectivity and % conversion over an 8‐hr period in a nitrogen‐purged system. The results exhibited a similar trend to catalyzed studies wherein an increase in temperature and molar ratio leaned towards the production of triglycerides (TG). It was also noted that tested initial water contents had an insignificant effect on reaction rates and product selectivity. Addition of molecular sieves for removal of water also resulted in negligible effects within this temperature range. DG production is optimum at 175°C and 2:1 molar ratio at 4 hr resulting in a product containing 42.6 ± 0.92 wt.% DG and a process selectivity of 1.11 ± 0.06 g DG/g (monoglycerides + TG). Purification by silica gel column chromatography of the product with the highest selectivity resulted in an enriched mixture with a yield of 58.25% and purity of 86.95 wt.% DG. Compared with catalyzed reactions, this system would require less downstream processing as removal of catalysts is not required and saponification does not occur. Although this procedure involves higher reaction temperature compared with enzyme‐catalyzed reactions, the time required to obtain high conversion is much shorter.