In flexible electronics, plastic substrates can limit processing temperatures to less than 100° C. Consequently, most semiconductors, including amorphous silicon, may be incompatible with temperature-sensitive plastic substrates. While organic semiconductors may seem well suited to this particular application niche, their stability is questionable and their mobility is often low (∼0.1 cm2/V-s). In this paper we show that ZnO is a promising semiconductor candidate for flexible electronics, because thin film transistors can be fabricated at room temperature with higher mobility (> 1 cm2/V-s) and high on/off ratio (> 104).