The shear wave velocity (V_s), which is directly related to the small strain shear modulus, G_max, can be measured by both field and laboratory tests and has a great potential in applications to various geotechnical problems. Soil exhibit nonlinear stress-strain behavior from very small strains and the reliable strain dependent modulus is usually determined by combining G_max obtained from field seismic test and G/G_max curve from the laboratory test. Therefore, the Vs is a key soil parameter for the deformation analysis of geotechnical structures. In this paper, the advantages of using Vs in geotechnical applications are discussed. The main features of various intrusive and non-intrusive Vs measuring techniques in the field, resonant column, torsional shear and bender element tests in the laboratory, and bender tomography in centrifuge model are summarized. Test results obtained by various field tests, laboratory element tests, and centrifuge models are compared and critically discussed considering parameters affecting soil stiffness as well as reliability of the test results. The V_s has been traditionally applied to earthquake related problems but its use has expanded to cover even the static deformation analysis problems. In this study, three cases of using V_s to geotechnical problems are introduced: (1) Evaluation of K_o value using V_s in centrifuge model, (2) settlement prediction of shallow foundation using V_s profile, and (3) evaluation of ground improvement and densification using V_s. The background theory, procedure, laboratory and field tests, physical modeling, and case studies for each application are discussed.