Settling behavior of clay minerals is very important when one considers that the fabric of soils largely governs engineering properties of soils. Although extensive research has been conducted to determine engineering proper-ties such as shear strength and consolidation etc, limited research has been conducted on settling behavior of clays that controls soil fabric/structure, which ultimately governs engineering behavior of soils. Thus, understanding of soil settling characteristics, and factors affecting the settling characteristics are essential for fully understanding and interpretation of engineering behavior of soils. In this study, settling behaviors and zeta potential of kaolinite as a function of pH and ionic concentration were determined. The results show a good correlation between the zeta potential and sediment thickness of kaolinite.