Provided herein are phosphothiophene and phosphothiazole compounds, for example, of any of Formulae I, IA, IIA, IIIA, IVA, VA, VIA, VIIA, IB, IIB, IIIB, IVB, VB, VIB and VIIB disclosed herein, pharmaceutical compositions comprising the compounds, and processes of preparation thereof. Also provided are methods of their use for the treatment of an HCV infection in a host infected with HCV.