The structure of La1-xNdxGaO3 (x = 0.07, 0.12, 0.17, and 0.20) solid solution single crystals were refined by the Rietveld method using X-ray powder data. All crystals belong to the GdFeO3 type structure (space group Pbnm, Z = 4). The a and c lattice constants decrease with increasing Nd concentration, whereas the b parameter slightly rises: a = 5.51667(6)-5.50279(8), b = 5.49006(7)-5.49054(8). and c = 7.77003(9)-7.7663(1) Angstrom. Although La-Nd substitution leads to the convergence of perovskite cell constants, only the La1-xNdxGaO3, structure dimensionally tends to be cubic. The deformation parameters such as bond-length distortion of polyhedra, degree of octahedra tilts, and distortion of R-R, R-Ga, and Ga-Ga distances, demonstrate an increase of deformation of perovskite structure during La-Nd substitution.