Aurivillius phase BaBi₄Ti₄O₁₅ micro-sized powders were produced by solid-state reaction and their photocatalytic properties were reported for the first time. X-ray diffraction revealed the polar orthorhombic structure. BaBi₄Ti₄O₁₅ ceramics exhibited diffuse phase transition at ∼ 410°C. The freezing temperature of 274°C was obtained by fitting the Vogel–Fulcher law. The distinct ferroelectric domain switching current peaks in current – electric field (I-E) loop and piezoelectric coefficient d₃₃ value of 7.0 ± 0.1 pC/N at room temperature further demonstrated relaxor ferroelectric behaviour of BaBi₄Ti₄O₁₅. UV-vis absorption spectra indicated that BaBi₄Ti₄O₁₅ had a direct band gap of 3.2 eV. The photocatalytic study showed 15% degradation of Rhodamine B (RhB) solution by BaBi₄Ti₄O₁₅ powders after 3.5 h UV-vis irradiation. The RhB degradation rate was further enhanced by depositing Ag nanoparticles on the BaBi₄Ti₄O₁₅ powders surface. This work suggested that the relaxor ferroelectric BaBi₄Ti₄O₁₅ is promising for photocatalytic applications.