Abstract Lattice constants of the garnets {Gd 3 } [Gd 0.03 Ga 1.97 ] (Ga 3 )O 12 , {Y 3 } [Y 0.505 Ga 1,495 ] (Ga 3 )O 12 , Y 3 Fe 4 GaO 12 , {Y 3 } [In 0.6 Ga 1.4 ] (Ga 3 )O 12 , {Ca 2 La} [Zr 2 ] (Ga 3 O 12 , {Y 1.05 Ca 1.95 }Ti 1.95 Ga 3.05 O 12 , Ca 3 Sn 3 Ga 2 O 12 , {Ca 2.5 Zr 2.5 } [Zr 2 ] (Ga 3 )O 12 , {Na 2 Ca} [Zr 2 ] (Ge 3 )O 12 have been measured in the temperature range 296–1400°K. The most important results are: 1) Crystals in the system {Y 3 } [Y x Ga 2−x ] (Ga 3 )O 12 are potentially good substrates for epitaxial films of the system Y 3 Fe 5−x Ga x O 12 and 2) Our Czochralski grown crystals of GdGaG actually have the formula {Gd 3 } [Gd 0.03 Ga 1.97 ]-(Ga 3 )O 12 ; the difference in the thermal expansions of the stoichiometric and Czochralski-grown materials is not significant.