Phototransistors based on multilayer MoS2 crystals are demonstrated with a wider spectral response and higher photoresponsivity than single-layer MoS2 phototransistors. Multilayer MoS2 phototransistors further exhibit high room temperature mobilities (>70 cm(2)V(-1)s(-1)), near-ideal subthreshold swings (similar to 70 mV decade-1), low operating gate biases (<5 V), and negligible shifts in the threshold voltages during illumination.