In this brief, a 2–10 GHz reconfigurable power amplifier (PA) with power-added efficiency (PAE) of 30% and output power of 2W is proposed using commercial <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.25~\mathbf {\mu }\text{m}$ </tex-math></inline-formula> GaN technology. It consists of two-stage amplifier transistors with reconfigurable input, inter-stage and output matching networks. By utilizing the reconfigurable matching networks, the proposed PA circuit divides the frequency band of 2–10 GHz into three continuous sub-frequency bands, and achieves high power added efficiency and gain in each sub-frequency band. As a result, the proposed PA can simultaneously maintain high efficiency and high gain and cover multioctave bandwidth. Moreover, in order to further improve the efficiency, harmonic suppression is used in low-band with open circuit impedance at third harmonic. With these techniques, the proposed PA covers frequency band of 2–10 GHz, delivers an average PAE of 38% at 2–5 GHz, 31% at 5–7 GHz, and 31.5% at 7–10 GHz. Good agreement between simulation and measurement is obtained.