This study aims to use local materials, particularly soil and date palm fibers, to develop a high-performance building material capable of improving the durability of earthen buildings in arid regions, primarily in NKOB-Zagora, located in the Drâa-Tafilalet region of Morocco. The main objective is to study the physical, mechanical, and thermal properties of compressed earth bricks (CEB) reinforced with raw and treated date palm fibers. Two types of fibers were used in this study: fibers from the leaflets (DPLF) and surface fibers (DPSF). These fibers were modified through two treatments: an alkaline treatment and a hydrothermal treatment. Initially, the soil and fibers, in both raw and treated states, were characterized. Then, CEBs reinforced with treated and untreated fibers, varying from 0 to 2% by weight, were prepared. The results show that the addition of both types of fibers, DPSF and DPLF, whether raw or treated, significantly improves the thermal insulation of CEBs while reducing their density. Furthermore, the incorporation of raw DPSF and DPLF results in a significant decrease in compressive strength, by 22.33% and 25%, respectively. Moreover, the results show that the applied treatments substantially mitigated this loss: for DPSF, the decrease was limited to 9.51% with alkaline treatment and 13.83% with hydrothermal treatment, for DPLF, reductions were limited to 13.45% and 16.75%, respectively. These results indicate that the use of date palm fibers as reinforcement improves the thermal performance of CEBs; furthermore, the applied treatments have limited the loss of mechanical properties.