A fiber-optic temperature sensor configuration is presented. This configuration consists of a fiber structure made from a no-core optical fiber coated with a thermochromic material as a transducer element between two multimode fibers. The excitation wavelength selected was in the absorption spectrum of the thermochromic material. The proposed sensor had a sensitivity of −0.08895  dB  /    °  C with a linear adjusted R-square of 0.9964 in a temperature range of 27°C to 63°C. The sensor response was characterized and validated with a commercial electronic temperature sensor.