Subwavelength-period gratings exhibit a number of interesting polarization-selective properties. We investigate several such phenomena: an `inverse' wire-grid polarizer, which transmits TE light while stopping TM light, a guided-mode resonance filter with an order-of-magnitude difference in the width of the reflectance peak for the two orthogonal states of polarization, a metal-coated silicon grating that reflects only TM-polarized light while absorbing the TE-polarized field component, and a metallic polarizing beamsplitter.