This study investigated the effect of pine resin on the thermal and mechanical properties of gypsum plasters with pumice aggregate. Pumice rock was crushed and sieved into three grain sizes (2-5 mm, 5-8 mm, and 8-12 mm). Each group was mixed separately with non-resinous and resinous gypsum in the proportions of 20%, 40%, 60%, and 80%. The resin was added to the gypsum at 2% of its total weight (gypsum + pumice) to generate artificial pores and improve the binding power of the gypsum. Twenty-four samples were produced in different combinations. The test results showed that resin reduced the thermal conductivity and improved the compressive stress of the plasters. They had a water absorption of greater than 30%, suggesting that they can be used in interior plasters and painted with any paint. In conclusion, they can be used as interior plasters for both insulation and strength