Inverse analysis methods were evaluated for determining thermal properties of materials for pyrolysis models. Experiments and analyses focused on determining the thermal conductivity and specific heat capacity of materials as a function of temperature and in different states. Experiments were designed to limit the properties (thermal conductivity, specific heat capacity) controlling the thermal response, allowing for more accurate determination of properties. Experiments and analyses were performed on three different materials: Ceramic, E-glass vinyl ester composite, and char/glass reinforcement. Results from the inverse analysis were compared with properties measured using other ASTM standard tests for measuring thermal properties. Properties were predicted to within 10 % of values from other standard test methods with quadratic and linear functions providing similar properties. Materials with more nonlinear variation in properties with temperature may require using quadratic functions to adequately predict properties.