Relying on nanoindentation technology, we investigated the elastic-to-plastic transition via first pop-in event and estimated the corresponding shear stress for incipient plasticity, i.e., yielding in the three typical orientations, i.e., X-112° / , Y-36° / , and Y-42° / planes. The occurrence of incipient plasticity exhibited a stochastic distribution in a wide range for the three orientations. Accordingly, the obtained values of yield stress were uniform and scattered in the range from about 4 to 7 GPa for LiTaO3 single crystal. The orientation effect on yield stress at the nano-scale was revealed to be insignificant in LiTaO3 single crystal. The yield stresses were 5.44 ± / 0.41, 5.74 ± / 0.59, and 5.34 ± / 0.525 GPa for the X-112° / , Y-36° / , and Y-42° / planes, respectively. The activation volumes of dislocation nucleation were computed based on the cumulative distribution of yield stress, which were 12 Å / 3, 8 Å / 3, and 9 Å / 3 for the X-112° / , Y-36° / , and Y-42° / planes. The results indicated that point-like defects could be the source of plastic initiation on the surface of LiTaO3 single crystal.