<p>This study investigates the influence of foliation on the mechanical behavior and fracture characteristics of transversely isotropic gneiss under tensile stress. Brazilian splitting tests were conducted on disc-shaped specimens with five anisotropy angles (<i>β</i> = 0°, 30°, 45°, 60°, and 90°). By integrating acoustic emission (AE), digital image correlation (DIC), and 3D laser scanning techniques, the evolution of microfractures and fracture surface characteristics was revealed. The results show that P-wave velocity increases from 3.42&#xa0;km/s at <i>β</i> = 0° to 4.23&#xa0;km/s at <i>β</i> = 90°, while the tensile strength decreases from 7.25&#xa0;MPa to 2.93&#xa0;MPa, indicating pronounced anisotropy. Three distinct failure patterns were identified: central failure (<i>β</i> = 0°), mixed failure (<i>β</i> = 30°, 45°, and 60°), and layer-activation failure (<i>β</i> = 90°). AE and DIC monitoring revealed that central fractures, governed by tensile stress, consistently initiated near the specimen center and propagated bilaterally, enabling reliable strength determination. In contrast, non-central fractures formed parallel to foliation planes exhibited a mixed tensile–shear mechanism and propagated inward from the specimen edges. Fracture surface roughness, characterized by relative height (RH) and the joint roughness coefficient (JRC), was found to gradually decrease with increasing <i>β</i>, a trend consistent with the variations in tensile strength and AE energy. These findings provide valuable insights into the tensile fracture mechanisms of gneiss controlled by anisotropy.</p>