The crystal structures of the double perovskites Ba2CePbO6, Ba2PrPbO6, and Ba2TbPbO5.90 have been refined by Rietveld analysis of time-of-flight neutron powder diffraction data. All three phases contain completely disordered B-cations. Diffraction and chemical analysis data indicate that Ba2TbPbO5.90 is slightly oxygen deficient.