We report a broad-band, linear, push-pull amplifier that utilizes GaN-based HEMTs grown on SiC substrates. The amplifier used a new broad-band low-loss balun implemented with three symmetric coupled lines. Using two 1.5 mm HEMTs with 0.35 mum gate length, a push-pull amplifier produced a small-signal gain of 8 dB at 5 GHz and 3 dB bandwidth of 3 - 10 GHz, with promising power and linearity performance.