The dataset contains output files of quantum-chemical calculations done using the CRYSTAL14 v. 1.0.3d code. All parameters are found in the beginning of the CRYSTAL output files with the file extension .o. In general, vibrations and lattice thermal conductivity of Cu2O were calculated using both a GGA-DFT functional and a hybrid-DFT functional and a TZVP sized basis set was used for all calculations. Outputs named supercell-xxxxx.o are used for Phono3py for post-processing calculations. For more information, please see paper https://doi.org/10.1103/PhysRevB.96.014304 .