 Titanium dioxide is a promising photocatalyst and has been widely used in many applications. However, it remains challenging to improve the photocatalytic performance of TiO2 under visible light illumination. Herein, a facile one step method was put forward to produce Mn-doped TiO2 nanotube arrays (TNTs) without the formation of manganese oxides. Intermediate band states were generated in Mn-doped TNTs, leading to enhanced visible light absorption and more efficient separation of photo-generated electron–hole pairs. The visible light photocatalysis of Mn-doped TNTs was significantly improved. The method reported here might be extended to the doping of other elements in TNTs and provides opportunities for the design of advanced photocatalysts.