SrBi 2−x La x Nb 2 O 9 (x=0, 0.05, 0.1, 0.2 and 0.35) ceramics were prepared by a conventional solid-state reaction method. Their structure and dielectric properties were investigated. X-ray diffraction analysis showed that single-phase layered perovskites were obtained. A relaxor like transition was observed in SrBi 2−x La x Nb 2 O 9 with x=0.2 and 0.35. For the specimens with x=0.05 and 0.1, a relaxation-type dielectric loss peak was observed in the temperature range of 30–150°C. The temperature of the maximum dielectric constant T m decreases linearly with increasing La content. The degree of frequency dispersion ΔT m , which is the T m difference between 10kHz and 1MHz, increases from 0°C for x=0–7°C for x=0.35. However, when x=0.1, ΔT m equals −1°C, which might be attributed to oxygen-vacancy-induced dielectric relaxation. In addition, La substitution results in a decrease in both remanent polarization and coercive field.