Abstarct: Dispersion is a process in which clayey soil is easily eroded by low-salt water. The failure to understand soil dispersion could lead to damage to hydraulic and other structures constructed on dispersive soils. The present study aims to evaluate the effects of potassium sulfate on the dispersion and strength of clayey soils. To this end, the effects of potassium sulfate on the physical, chemical, and strength properties of dispersive clay specimens from the Kalaleh catchment were studied. The specimens were subjected to primary tests. Then, potassium sulfate (K2SO4) was added at dry soil mass fractions of 0%, 0.5%, 1.0%, 1.5%, and 2.0% at the optimum moisture content (OMC). The dispersion potential of the specimens was measured using chemical, pinhole, and double hydrometer tests. In addition, the strength parameters of the soil were evaluated using uniaxial tests at curing ages of 1, 7, and 28 days. It was found that potassium sulfate reduced or eliminated the dispersion potential. Furthermore, potassium sulfate at a mass fraction of 2.0% enhanced the compressive strength by 23.2% and 78.9% at curing ages of 7 and 28 days, respectively, compared to the control specimen.