Phase-change wax-based printed masks, in place of conventional photoresist masks, were used to fabricate a-Si:H thin-film transistors (TFTs). Printed wax-mask features with a minimum feature size of ∼20 μm were achieved using an acoustic-ink-printing process. Both discrete and matrix addressing structured bottom-gate TFTs with sourcedrain contacts overlapping the channel were created using a four-mask process. The TFTs had I-V characteristics comparable to photolithographically patterned devices, with mobility of 0.6-1 cm²/V·s, threshold voltage of 2-3 V, and on/off ratios exceeding 10⁷ for devices with channel lengths below 50μm. The wax-mask process was also used to fabricate self-aligned TFT devices, eliminating the sourcedrain contact overlap constraint.