The infrared and Raman vibrational spectra of the series of solid tris(dipivaloylmethanato) lanthanides, Ln(thd)3 (Ln = La, Nd, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu), have been recorded at room temperature over wide ranges (4000–50 cm−1 and 3500–80 cm−1, respectively). The experimental spectra obtained in the present study were successfully assigned based on the quantum chemical calculations (DFT/PBE0) performed for the monomer Ln(thd)3 molecules. The experimental vibrational spectra for all complexes studied are rather similar as are the theoretical simulations. The data analysis shows that the main contributions to vibrational modes arise from the vibrations of the ligand possessing practically the same geometry for all complexes. According to the calculation results the structure of the coordination polyhedron is increasingly distorted in the series from La(thd)3 to Lu(thd)3. Although the contributions of the polyhedron vibrations in vibrational modes are not predominant, there is rise in the frequencies associated with vibrations of the coordination polyhedron LnO6 in this series. This increase has been explained by the concept of lanthanide contraction.