An LR polyphase filter implemented with inductors and resistors and capable of operating at high frequencies is described. In one design, the LR polyphase filter includes first and second paths, with each path including an inductor coupled to a resistor. The first and second paths receive a first input signal and provide first and second output signals, respectively, which may be in quadrature. For a differential design, the polyphase filter further includes third and fourth paths, which receive a second input signal and provide third and fourth output signals, respectively. The four output signals may be 90° out of phase. The first and second input signals are for a differential input signal. The first and third output signals are for a first differential output signal, and the second and fourth output signals are for a second differential output signal. Each inductor may be implemented with a transmission line.