An RF amplifier includes an amplifier input, a transistor die with a transistor and a transistor input terminal, a fundamental frequency impedance matching circuit coupled between the amplifier input and the transistor input terminal, and a harmonic frequency termination circuit coupled between the transistor input terminal and a ground reference node. The harmonic frequency termination circuit includes a first inductance coupled between the transistor input terminal and a first node, and a tank circuit coupled between the first node and the ground reference node. The tank circuit includes a first capacitance coupled between the first node and the ground reference node, and a second inductance coupled between the first node and the ground reference node. The tank circuit is configured to shunt signal energy at or near a second harmonic frequency, while appearing as an open circuit to signal energy at a fundamental frequency of operation of the RF amplifier.