<p>The compressibility and swelling of clayey soils are a critical factor in geotechnical engineering, particularly in settlement analysis and foundation design. The effect of dominant clay minerals on the compressibility like compression index (c_c), coefficient of consolidation (c_v), and swelling parameters, such as swelling index(c_s) has been extensively studied, but the impact of chemical properties like cation exchange capacity (CEC) and specific surface area (SSA) remains limited. The electrical physical and chemical forces that influence soil behavior, are complex and difficult to measure directly. However, CEC and SSA are indirect indicators of the forces influencing clayey soil behaviour, providing valuable insights into their compressibility and swelling behaviour. This study investigates the effect of these chemical properties, in conjunction with the dominant clay mineral, on the compressibility and swelling behavior of natural clay soils. Laboratory tests were conducted on 20 clayey soils collected from various districts of Tamil Nadu. All 20 soil samples were categorized into three groups based on the dominant clay mineral like montmorillonite, kaolinite, and illite-dominated soils. The results indicated that montmorillonite-dominated soils have shown a steep increase in c_c and c_s with respect to CEC and SSA, and c_c and c_s have shown better relationships with SSA (<i>R</i>² &gt; 0.75) than CEC. For the applied consolidation pressure σ, c_v decreases with an increase in CEC and SSA for montmorillonite-dominated soils, whereas it increases under the same conditions for kaolinite and illite-dominated soils.</p>