Nd:Sr 3 Ga 2 Ge 4 O 14 (Nd:SGG) crystals with different Nd 3+ concentrations have been grown by the vertical Bridgman method. The influence of the Nd 3+ concentrations on lattice parameters and thermal conductivity were investigated. The lattice parameters are linear functions of the Nd 3+ concentrations; the structure distortion is relatively small when Nd 3+ concentration is lower than 1.5 at.%. The thermal diffusivity was investigated as a function of Nd 3+ concentrations for the first time; from this, the thermal conductivity of 1.5 at.% Nd-doped SGG crystals was calculated. The results indicate that the thermal conductivity of Nd:SGG is similar to those of laser glasses.