Successful depletion and management of, e.g., petroleum, geothermal, and reservoirs for CO2 storage often depend on reliable laboratory estimates of mechanical rock properties such as stiffness and strength. Accordingly, reducing uncertainty and quantifying a potential impact on estimates from testing temperature may be essential for successful depletion and reservoir management. Rock stiffness and strength data collected at elevated temperatures are often limited, stressing the importance of theoretical knowledge on mechanisms controlling temperature-induced changes in mechanical rock properties for predictions purposes. Chalk reservoirs across the world are abundant as producing petroleum reservoirs, and in the Danish North Sea sector is most petroleum production from Upper (late) Cretaceous chalk reservoirs. However, this project focuses on the less abundant Lower (early) Cretaceous chalk reservoirs, where our knowledge of the chalk’s mechanical properties are limited, distinctly concerning effects of temperature.