A new whisker, alpha-MoO3, was fabricated via molybdenum thread oxidation at 973, 1023, and 1173 K. Various morphologies of the whiskers, such as flakelike, platelike, and needle-like, were observed under different fabrication conditions. The lateral surfaces of the whiskers were close-packed (010) plane, and the growth direction was [001], which related to the unique layered structure of the alpha-MoO3 crystal. Growth of the MoO3 whiskers was attributed to a vapor-liquid-solid (VLS) mechanism at 1023 and 1173 K, whereas, at 973 K, growth was attributed to a vapor-liquid (VL) mechanism.