The use of earth blocks in construction is often limited by their low mechanical strength and sensitivity to moisture. Although conventional stabilizers, such as Portland cement, improve strength, they also increase cost and environmental impact. This investigation quantifies the effectiveness of geopolymers as stabilizing agents for compressed soil blocks at concentrations ranging from 0% to 6% by weight. Significant performance improvements were revealed by mechanical testing. Compressive strength increased by over four times to reach 4.076 MPa, compared to 0.892 MPa for the control sample. Tensile strength also increased, by over five times, to reach 0.648 MPa, compared to 0.114 MPa for the control sample. This is due to the formation of an aluminosilicate matrix through polymerization, which binds the soil particles together. This study also establishes geopolymers as a viable, environmentally friendly solution for reinforcing earthen building materials.