La doped barium titanate particles were prepared by the sol–gel method. The structure and microwave absorption properties of the Ba1−xLaxTiO3 particles (x varies from 0% to 1.0% in steps of 0.4%) were characterized by the methods of X-ray diffraction (XRD), Raman spectroscopy and vector network analyzer. All samples are found to be single phase with tetragonal BaTiO3 structure, the existence of long-range lattice disorder, local polar ordering and A-site La3+ defects, respectively. Barium titanate with x > 0 exhibited significant dispersion in complex permittivity. The dispersion in complex permeability was not significant. The variations of reflection loss were studied as a function of frequency and La3+ content. For sample with x equal to 0.6%, a minimum reflection loss of −41.0 dB was obtained. The bandwidth with loss above −10 dB was more than 1.7 GHz. It means that the doping of La ions can greatly improve the microwave absorption properties of the materials.