The effect of lattice mismatch (stress) on magnetic anisotropy is studied in epitaxial films of a Eu0.65Y2.35Fe3.8Ga 1.2O12 garnet grown on a series of garnet substrates with different lattice parameters. These garnet films have a negative magnetostrictive coefficient (λ ≃ 0.5 × 10-6) as predicted by simple magnetic dilution theory. A "growth"-induced magnetic anisotropy (Ku ≃ 8300 erg/cm3) will exist for all of these films even when they are grown on a substrate with a perfect lattice match. Anisotropy can be increased by using an increased substrate rotation rate during film deposition. © 1973 American Institute of Physics.