Silver (Ag) nanoparticles decorated NaNbO3 nanorods (Ag-NaNbO3) based nanocomposite have been successfully synthesized by simple chemical solution method with the aim to couple the plasmonic and piezo-phototronic effect. The Ag-NaNbO3 nanocomposite showed much enhanced photocatalytic and photoelectrochemical water splitting properties as compared to bare NaNbO3. A similar to 10 fold enhancement in the photodecomposition of organic MB dye and a similar to 9 fold increment in the photocurrent density of photoelectrochemical water splitting was observed as compared to bare NaNbO3, which has been attributed to the combined plasmonic and piezo-phototronic effect. The plasmonic effect due to the presence of Ag nanoparticles on the NaNbO3 surface resulted in enhanced absorption of visible light and piezo-photoelectric effect resulted in better separation of the photogenerated charges due to the built-in electric field. This approach demonstrates a novel strategy for enhancing the performance of silver decorated semiconducting/piezoelectric material for achieving efficient photocatalytic dye degradation and PEC water splitting. (C) 2020 Elsevier Ltd. All rights reserved.