In this study, 5,10,15,20-tetrakis(p-chlorophenyl)porphyrin has been synthesized and used as an ionophore for the preparation of a poly(vinyl chloride) (PVC) membrane sensor for aluminium(III) ions. The optimum composition of the best performing membrane contained ionophore, bis(2-ethylhexyl) adipate, PVC and potassium tetrakis(p-chlorophenyl) borate in the ratio of 4.0:63.0:32.0:1.0 (mg). The prepared PVC membrane morphology has been analysed by scanning electron microscopy. The developed aluminium(III)-selective sensor works in a wide linear concentration range of 1.0 x 10(-5) to 1.0 x 10(-1) mol l(-1) and, the detection limit of this sensor is 2.81 x 10(-6) mol l(-1). The sensor displays near-Nernstian slope of 25.0 +/- 2.7 mV per decade for Al3+ ions. The aluminium(III)-selective sensor has a wide working pH range of 5.0-10.0. The sensor shows good reusability, long-term stability and a fast response time of less than 5 s. In addition, the sensor shows good selectivity for Al3+ ions over different cations. This aluminium(III)-selective sensor was successfully used as an indicator electrode in the potentiometric titration of Al3+ ions with EDTA. The developed sensor was successfully applied to the direct determination of Al3+ in different water samples.