A series of lanthanide oxide-doped titanium dioxide photocatalysts Ln(2)O(3)/TiO2 (Ln(3+) = Eu3+, Pr3+, Yb3+) were prepared. The photocatalysts reveal a substantially enhanced activity for the degradation of organic pollutants, as compared to undoped TiO2. The photodegradation processes of p-nitrobenzoic acid, (1), p-chlorophenoxyacetic acid, (2), aniline, (3), salicylic acid, (4), and trans-cinnamic acid, (5), with the different photocatalysts was examined. The photodegradation of (1)-(5) is significantly faster with Ln(2)O(3)/TiO2 photocatalysts and leads to complete mineralization of the organic compounds. The high activity of the Ln(2)O(3)/TiO2 photocatalysts is attributed to the enhanced association of the functionalized organic pollutants to lanthanide-ion surface sites.