Tungsten oxide (WO3) nanostructures of controlled morphology were successfully synthesized by hydrothermal method. The size, shape and crystal structure were tuned by varying amount of precursor and structure directing agent. TEM and XRD measurements confirm the formation of hexagonal and monoclinic nanostructures. The synthesized WO3 nanostructures exhibit excellent photocatalytic and sensing properties. The photocatalysis was performed at room temperature by varying three different organic dyes i.e. Methyl Blue (MB), Methyl Orange (MO) and Rhodamine B (RhB) under UV irradiation. The photocatalytic efficiencies were optimized considering the effects of catalyst amount, dye concentration, calcination temperature and pH. Moreover, the WO3 nanostructures reveal excellent electrocatalytic properties for sensing of H2O2 and L-Cysteine. The WO3/GCE modified electrode shows highly reproducible sensitivity of 4.99 mu A mu M(-1)cm(-2) and 0.301 mu A mu M(-1)cm(-2) for H2O2 and L-Cysteine, respectively. Moreover, the modified electrode exhibits a low detection limit of about 0.5 mu M and wide linear detection range from about 0.5 to 50 mu M for H2O2 and a low detection limit of about 3 mu M and wide linear detection range from about 3 to 50 mu M for L-cysteine, respectively. Our results demonstrate that WO3 nanostructures with multifunctional properties can be employed for remediation of environmental issues and sensing applications.