The effect of ZrO2 on crystallographic order, microstructure, and microwave dielectric properties of Ba(Zn1/3Ta2/3)O-3 (BZT) ceramics was investigated. A small amount of ZrO2 disturbed the 1:2 cation ordering. The average grain size of the BZT significantly increased with the addition of ZrO2, which was attributed to liquid-phase formation. The relative density increased with the addition of a small amount of ZrO2, but it decreased when the ZrO2 content was increased. Variation of the dielectric constant with ZrO2 addition ranged between 27 and 30, and the temperature coefficient of resonant frequency increased abruptly as the ZrO2 amount exceeded 2.0 mol%. The Q value of the BZT significantly improved with the addition of ZrO2, which could be explained by the increased relative density and grain size. The maximum Qxf value achieved in this investigation was similar to164 000 GHz for the BZT,with 2.0 mol% ZrO2 sintered at 1550degreesC for 10 h.