Gd–La codoped Ti O2 nanoparticles with diameter of 10 nm were successfully synthesized via a sol–gel method. The photocatalytic activity of the Gd–La codoped Ti O2 nanoparticles evaluated by photodegrading methyl orange was significantly enhanced compared to that of undoped or Gd or La mono-doped Ti O2. Ti4+tmay substitute for La3+tand Gd3+tin the lattices of rare earth oxides to create abundant oxygen vacancies and surface defects for electron trapping and dye adsorption, accelerating the separation of photogenerated electron–hole pairs and methyl orange photodegradation. It is believed that the formation of an excitation energy level below the conduction band of Ti O2 from the binding of electrons and oxygen vacancies decreases the excitation energy of Gd–La codoped Ti O2, resulting in versatile solar photocatalysts. The results suggest that Gd–La codoped Ti O2 nanoparticles are promising for future solar photocatalysts. The photocatalytic activity of the Gd-La codoped Ti O2 nanoparticles evaluated by photodegrading methyl orange was significantly enhanced compared to that of undoped or Gd or La mono-doped Ti O2. Ti4 + tmay substitute for La3 + tand Gd3 + tin the lattices of rare earth oxides to create abundant oxygen vacancies and surface defects for electron trapping and dye adsorption, accelerating the separation of photogenerated electron-hole pairs and methyl orange photodegradation. It is believed that the formation of an excitation energy level below the conduction band of Ti O2 from the binding of electrons and oxygen vacancies decreases the excitation energy of Gd-La codoped Ti O2, resulting in versatile solar photocatalysts. The results suggest that Gd-La codoped Ti O2 nanoparticles are promising for future solar photocatalysts.