Desertification stands as a major global issue, while the scarcity of renewable energy sources continues to be a growing concern. To address these challenges, the use of desert sand as a fine aggregate in sustainable concrete has been explored. Desert sand offers numerous advantages such as environmental protection, cost savings, and energy efficiency. This paper examines the impact of treated desert sand on the mechanical and microstructural properties of sustainable concrete. The results of this study reveal that the highest compressive strength was achieved with a 50% replacement level of treated desert sand. The concrete mixture with 50% desert sand achieved the highest 28-day compressive strength at 61.06 MPa. Conversely, the lowest 28-day compressive strength of 41.73 MPa was observed in the concrete mix containing 100% treated desert sand while the control mix with 0% treated desert sand attained a 28-day compressive strength of 48.7 MPa. As the proportion of treated desert sand increased, the workability of concrete decreased. The slump value, which was initially 130 mm for the control mix, dropped to 80 mm in the concrete mix composed of 100% treated desert sand. However, the flexural and tensile strengths tended to decrease as the amount of desert sand increased, particularly beyond a 25% replacement level. The addition of desert sand improves compactness and reduces pores in the samples, as observed through Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy Analysis (EDS) analysis. The results suggest that desert sand can be effectively treated using different treatment methods and used as a fine aggregate in various applications within the construction industry. This research sheds light on the potential of desert sand in sustainable concrete production, contributing to environmental preservation and resource conservation efforts.