Advanced oxidation processes (AOPs) have been reported as alternative ways for treating reverse osmosis (RO) concentrate which is the primary concern for water reclamation plants. AOPs are known to oxidize recalcitrant organic compounds by a highly reactive and nonselective oxidant, hydroxyl radical (·OH). Researchers showed that AOPs such as the conventional Fenton, UV/H2O2, ozonation, electrochemical oxidation processes could remove organics in RO concentrate. However, comparing different AOPs has been rarely performed for the treatment of RO concentrate. In addition, the cost of these processes has not been fully explored. In this study, five different AOPs (i.e., the conventional Fenton, UV/H2O2, ozonation, anodic oxidation, and electro-Fenton processes) were evaluated for the removal of dissolved organic carbon (DOC) in RO concentrate. The operation costs for DOC removal by these AOPs were also calculated. The results indicated that the conventional Fenton and ozonation processes were the most cost-efficient among the processes tested.