The crystal structure and dielectric characteristics were evaluated for Ba4Sm2Ti4Ta6O30 and Ba5SmTi3Ta7O30 ceramics. The X-ray diffraction patterns confirmed the tetragonal tungsten bronze structure with space group P4bm. A normal ferroelectric phase transition was observed at 332 K for the former, while the typical relaxor ferroelectric behavior with a spin glass nature was determined for the latter, where a broad permittivity peak with a strong frequency dispersion was observed around 150 K, which followed the Vogel-Fulcher relationship well. These different dielectric behaviors originated from the different crystal structures governed by the occupancy configuration of cations at A1 and A2 sites.