The recovery of rare earth elements (REEs) from primary and secondary resources can be hindered by impurities, including radioactive thorium (Th). Th removal prior to REE recovery is often necessary to ensure that product specifications are achieved. In this study, three ion-exchange resins were evaluated for selective Th removal from a synthetic multielement solution containing Ce, La, Nd, Sm, Gd, Dy, and Y, aiming to retain REEs in the aqueous phase. The resins were Lewatit® MonoPlus TP260, a chelating cation-exchange resin containing aminomethylphosphonic acid groups; Lewatit® MonoPlus MP64, a weak-base anion-exchange resin with a macroporous styrene-divinylbenzene matrix; and Lewatit® MonoPlus MP800, a Type I strong-base anion-exchange resin with quaternary ammonium groups. The starting solution comprises of 206 mg/L Ce, 104 mg/L La, 53 mg/L Nd, 8.5 mg/L Sm, 11 mg/L Gd, 5.8 mg/L Dy, 5.5 mg/L Y, and 50 mg/L Th. The resins were evaluated at pH 1–5 using 1.0 g resin per 50 mL solution and a 2 hr contact time. TP260 adsorbed 98–99 per cent Th and 83–97 per cent REEs, indicating that its aminomethyl-phosphonic acid groups did not provide sufficient discrimination between Th and REEs under the evaluated conditions. MP64 adsorbed 1835 per cent REEs, while Th adsorption increased from approximately 30 per cent at pH 1 to 70 per cent at pH 5. For MP800, Th adsorption increased from approximately 20 per cent at pH 1 to 99 per cent at pH 5. At pH 5, individual REE adsorption ranged from 11 to 29 per cent, corresponding to 71–89 per cent remaining in solution. This behaviour may be related to anionic Th species interacting with MP800 quaternary ammonium groups through ion exchange. The kinetic adsorption of Th onto MP800 at pH 5 was evaluated. Approximately 98 per cent Th was removed from solution after 0.5 hr and remaining at 98–99 per cent range up to 8 hrs. These results demonstrate the potential of MP800 for selective Th removal. Future studies will evaluate primary- and secondaryresource-derived solutions to investigate matrix composition and other elements on Th removal and REE retention.