Transparent lutetium oxide bodies were fabricated by spark plasma sintering. The effects of sintering temperature, applied pressure, and holding time on the density, microstructure, and transmittance of these bodies were investigated. Nearly fully dense specimens were fabricated at above 1573 K and 100 MPa for 2.7 ks or at 1673 K and above 40 MPa for 2.7 ks. The grain size and transmittance steadily increased with increasing sintering temperature from 1273 to 1723 K and abnormal grain growth occurred above 1723 K, resulting in a decrease of density and transparency.