Superplastic deformation behavior is examined for Al2O3-based ceramics dispersed with ZrO2 and spinel phases. The multiple-phase dispersion considerably decreases the rate of grain growth and lowers the flow stress, leading to enhanced superplasticity (larger tensile elongation and higher strain rate). A maximum strain rate of 1/s and a maximum tensile elongation of 2510% are recorded for a composite ceramic of Al2O3:ZrO2:spinel=3:4:3. The enhancement can be attributed to a fine microstructure and the suppression of cavitation, to which dislocation-induced plasticity in ZrO2 grains may contribute.