Illustrative methods and circuits to verify operation of phase shifters. One illustrative method includes: obtaining a first set of in-phase and quadrature components (I1,Q1) of a phase shifter output signal with a first setting; measuring a second set of components (I2,Q2) with a second setting, the second setting being offset from the first by a predetermined phase difference; and combining the first and second sets to determine whether their relationship corresponds to the predetermined phase difference. An illustrative transmitter includes: a phase shifter, an I/Q mixer, and a processing circuit. The phase shifter converts a transmit signal into an output signal having a programmable phase shift. The I/Q mixer mixes the output signal with a reference signal to obtain in-phase and quadrature components of the output signal. The processing circuit is coupled to the I/Q mixer implement the disclosed method.