Mn2O3 particles with enhanced crystallinity were synthesized via a precipitation process in aqueous solution. To study the effects of organic additives on the formation and crystallinity of Mn2O3, cetyltrimethylammonium bromide (CTAB) and tert-butanol (t-butanol) were used as a surfactant and cosurfactant, respectively. In addition, ammonium oxalate monohydrate (AOM) was employed as a chelating agent to control the activity of Mn2+ and the precipitation of particles. The magnetization of the products prepared by using more additives was improved owing to the increased crystallinity.