There is no clear evidence of elementary deformation processes were addressed so far, especially in the case of Al2O3 nanocrystals, while the ductility of ceramics at small scale would have primary engineering applications. In this study, we propose to investigate α-Al2O3’s nanomechanics and plasticity using molecular dynamics simulations at room temperature. Firstly, MD simulations are performed with single crystalline α-Al2O3 under nanoindentation. Four crystallographic orientations are investigated, m [1-100], a [2-1-10], R [-1012] as well as c [0001], including a detailed analysis of Al2O3 dislocation-based mechanisms. The results show that the O atoms occur phase transition, changing from HCP structure to FCC and BCC structures. Secondly, during nanoindentation, we focus on pop-in events and transition point from elastic to inelastic response during loading forces. The results are discussed in the context of recent TEM experiments, possibly opening new doors towards ceramic bulk material processes