The geochemical composition and radiogenic heat production (RHP) of granitoids from fourteen plutons in Egypt’s Eastern and Western Deserts was studied using inductively coupled plasma mass spectrometry (ICP-MS). The results show that light rare earth elements (LREEs) dominate over heavy rare earth elements (HREEs), and the Th/U ratios range from 1.75 to 6.81. RHP values vary significantly, from 1.31 to 9.17 µW/m³, with El Dib pegmatitic syenite showing the highest value and Abu Dabbab, the lowest. El Dib and Qattar granites are classified as high heat-producing rocks (HHP), while El Dokhan, El Sibai, Missikat, and Bir Safsaf granites fall into the moderate category (MHP). The remaining plutons are considered as low heat-producing (LHP), though their average RHP still exceeds the global upper continental crust average. No clear relationship was found between RHP and Th/U ratios or SiO2 content. γ-Ray spectrometry (GRS) proved to be a reliable complementary method for assessing RHP. Overall, the findings highlight the geothermal potential of these granitic intrusions as promising heat sources in Egypt’s desert regions.