This article reports the anodic growth of tungsten oxide (WO3) nanoplates in hydrochloric acid (HCl). Formation of nanoplates in HCl could be obtained by the assistance of applied potential. Increase of the applied potential results in a higher nucleation rate of the nanoplates while it has no significant effect on the nanostructured layer. Anodization temperature plays a crucial role in manipulating the morphological and structural properties of the nanoplates. As the temperature increases, maximum layer thickness of similar to 1.4 mu m could be reached while uneven-shaped nanoplates transform to larger square-shaped plate. All as-anodized samples exhibit hydrated WO3 crystalline. A possible growth mechanism of the nanoplates in HCl is also proposed. Photocurrent measurements revealed that sample anodized at room temperature for 15 h shows highest photocurrrent with 1 V applied voltage. However, without biased voltage, sample anodized at 40 degrees C for 4 h exhibit highest photocurrent. (C) 2014 The Electrochemical Society. All rights reserved.