A practical double-sensor multiplexed fiber optic displacement sensor is reported. The sensor is based on the principles of optical frequency-modulated continuous-wave (FMCW) interference and frequency-division multiplexing. The beat signals from the individual sensors are assigned in the frequency domain and separated with different electrical bandpass filters. The displacements of the targets can be determined simultaneously by detecting the phase shifts of the corresponding beat signals. The cross talks between the individual sensors are analyzed algebraically and with a phasor diagram. An accuracy of 0.05 µm in a dynamic range of 1000 µm is achieved.