The effects of pore water chemistry on the cyclic behavior of fine-grained soil were examined by performing undrained cyclic ring-shear tests on a natural soil treated with solutions of sulfuric acid (H2SO4), sodium hydroxide (NaOH), and sodium chloride (NaCl). In addition, different amounts of the chemicals were used to clarify the influence that ion concentrations in the pore fluid can have on the cyclic shear strength of soil. The results of laboratory tests indicated that cyclic shear strength was sensitive to changes in the pore fluid composition, and changes in cyclic behavior of soil became more pronounced as the concentration of each chemical increased.