One of the challenges to reduce energy consumption in the construction sector around the world is the development of appropriate construction materials. Due to its thermal properties, gypsum plaster is one of these materials. Tunisia ranks second worldwide for the production of gypsum. It used almost exclusively for decorative purposes although it has interesting thermal properties. This study deals with the thermal characterization of Tunisian gypsum plaster from Meknassi region. Particular attention is paid to the effect of temperature and water content on the thermal conductivity. The plaster thermal conductivity vs. temperature exhibits an interesting behavior for buildings walls. Thermal analysis by DSC was conducted to explain this behavior.