<p>Quality control of compressed earth construction materials remains a technical challenge, mainly due to the variability of raw materials and the absence of standardized non-destructive evaluation methods. This study proposes an original experimental approach to predict the mechanical performance of compressed earth blocks (CEBs), stabilized with wheat straw, using ultrasonic pulse velocity (UPV) measurements. A total of 120 blocks were manufactured according to an experimental design combining four levels of compaction energy (25, 50, 75, and 100 blows per layer) and five straw contents (0% to 8%). Each specimen was subjected to destructive tests (dry and saturated compressive strength) and non-destructive tests using UPV. Statistical analysis enabled the development of accurate regression models linking UPV measurements to the physical and mechanical properties of the blocks. The results show a very strong linear correlation between UPV and dry compressive strength (R² ≈ 0.97), a good prediction of saturated compressive strength (R² ≈ 0.96), and a moderate but consistent relationship with air-dry density. This novel approach shows that UPV can be a reliable and effective non-destructive indicator for monitoring the quality of fiber-reinforced CEBs within the investigated material system. The methodology developed in this work thus contributes to the valorization of bio-based materials and the optimization of quality control in sustainable construction sectors, while providing a reproducible and accessible protocol for resource-limited environments.</p>