The dielectric constants (&kgr;’) and dielectric loss values of 10 rare‐earth gallium garnets and 1 rare‐earth aluminum garnet were measured at 1 MHz using a two‐terminal method with empirically determined edge corrections. The results are: &kgr;’(Dy3Al5O12)=11.07±0.05; &kgr;’(Ho3Ga5O12) =12.38±0.05; &kgr;’(Dy3Ga5O12)=12.36±0.06; &kgr;’(Tb3Ga5O12) =12.40 ±0.03; &kgr;’(Gd3Ga5O12) =12.18±0.10; &kgr;’(Eu3Ga5O12) =12.46±0.05; &kgr;’(Sm3Ga5O12) =12.55±0.03; &kgr;’(Nd3Ga5O12) =12.59±0.12; &kgr;’(Y3Sc2Ga3O12) =12.94±0.03; &kgr;’(Sm3Sc2Ga3O12) =13.67±0.04; and &kgr;’(La2.66Lu2.66Ga2.66O12) =14.40±0.03. The dielectric polarizability of Ga2O3derived from the dielectric constants of these and other Ga compounds is 8.80±0.14 A˚3. The agreement between measured dielectric polarizabilities as determined from the Clausius–Mosotti equation and those calculated from the sum of oxide polarizabilities according to &agr;D(mineral) =&Sgr;&agr;D(oxides) for six aluminum garnets and twelve gallium garnets is ∼1%.