Ioannis Vardoulakis (Greek: Ιωάννης Βαρδουλάκης; 22 March 1949 - 19 September 2009) was an eminent scientist who is known for his major contributions in the modeling of geomaterials, geo-hazards and geotechnical processes. He was the pioneer of the bifurcation theory of geomechanics, which has led to a better understanding of the long-standing problem of mesh-dependency in the Finite Element Modeling. He also contributed to the enriched continuum modeling, which allowed for the first time the constitutive modeling of shear bands and worked extensively in experimental geomechanics, having developed ingenious devices to test geomaterials.