We have investigated the growth conditions, the magnetic properties and low‐field ferromagnetic resonance (FMR) properties of praseodymium‐substituted garnet films. Films of general composition Y3−x−yPrxLuyFe5O12, were grown by liquid phase epitaxy onto [111]‐oriented Gd3Ga5O12substrates. Vibrating sample magnetometry, torque magnetometry and FMR were used to measure saturation magnetization and the cubic and induced anisotropy constants. It is shown that the uniaxial anisotropy constantKuand the first order magnetocrystalline anisotropy constantK1, have a strong dependence upon the praseodymium content. The addition of praseodymium in the garnet films improves the soft magnetic properties. The effect of the doping by praseodymium on the saturation magnetization is insignificant at room temperature. In‐plane coercivity is about 0.1 Oe.