[en] The temperature dependence of hardness and microcracking in single-crystal 9.5-mol percent-Y₂O₃- fully-stabilized cubic-ZrO₂ was studied as a function of orientation. Crack lengths increased with increased temperature up to 500 degrees C; above 800 degrees C, no cracks were found, indicating an indentation brittle-to-ductile transition of ∼ 800 degrees C. The temperature dependence of hardness was reduced around 500 degrees C. Etching studies to delineate the plastic zone around and below indents identified the operative slip systems. The role of dislocations and their interactions within the plastic zone on the hardness and indentation fracture behavior of cubic ZrO₂ are discussed