Speckle tracking echocardiography (STE) was popularized in the first decade of this century. Analysis of cardiac mechanics has been the focus of ultrasonics, and the breakthrough came with STE. Beyond analysis solely of left ventricular ejection fraction, STE allows the assessment of various pathophysiologies, including myocardial layer-specific myocardial function, twist and rotation, and dyssynchrony. Recent developments in the technology have resulted in commercially available 3-dimensional (D)-STE systems. Through experimental studies and clinical investigations, the reliability and feasibility of 3D-STE-derived data have been validated, and the advantages of 3D-STE over 2D-STE have been revealed. In addition, because of the 3D nature of the technology, 3D-STE provides novel deformation parameters (ie, 3D-strain and area change ratio) that have the potential for more accurate assessment of overall and regional myocardial function. Recently, various preliminary studies using 3D-STE have reported on myocardial characteristics, novel mechanics in the left ventricle, prediction of therapeutic effects, observations of cardiac function through interventions, and challenges for left atrial and right ventricular functions. In this review, we focus on the features of the methodology, validation, and clinical application of 3D-ST.