This study was aimed at investigating and comparing the effects of exogenous glycinebetaine (GB) and trehalose (TR) on lead (Pb) accumulation in Lemna gibba. Two-way ANOVA showed that both GB and TR had significant effects on Pb accumulation. However, TR seemed to be more effective than GB. It was determined that 5 mM GB application decreased Pb accumulation whereas 0.5 mM TR increased and 2 and 5 mM decreased Pb accumulation. The results obtained from this study will be useful for examining the phytoremediation of polluted water using aquatic plants.