A fiber-based thermal property probe is disclosed. In embodiments, the thermal property probe is a modulated optical reflectance system and includes a pump beam source configured to transmit a pump beam through a pump fiber, the pump beam configured to heat a sample and the pump fiber having a pump fiber sample end. The fiber-based thermal property probe further includes a probe beam source configured to transmit a probe beam through a probe fiber, the probe beam configured to measure the temperature of the sample and the probe fiber having a probe fiber sample end. Additionally, the system includes a ferrule configured to hold the pump fiber sample end and the probe fiber sample end at a fixed, known separation distance from each other.