Zirconium carbide (ZrC) is a promising ultra-high-temperature ceramic (UHTC) for thermal protection systems (TPS) due to its high melting point, thermal stability, and mechanical strength. However, its susceptibility to oxidative degradation and limited thermal shock resistance poses challenges for aerospace applications. This thesis investigates how prior oxidation history (defined by exposure temperature and duration) influences the thermal shock response of the zirconia oxide scale on monolithic ZrC. Samples were oxidized at 600°C, 700°C, and 800°C for varying durations, followed by thermal shock via water quenching. Post-exposure analysis using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and mass change measurements showed that increasing oxidation severity leads to thicker, brittle oxide scales with higher monoclinic ZrO2 content and elevated crack densities. A transition to failure-prone behavior occurs between 700°C and 800°C, with failure thresholds defined by a ≥10% surface crack density and monoclinic ZrO2 content exceeding 10%. These results establish oxidation-dependent limits for ZrC’s thermal shock resistance.