Decolourization of C.I. Reactive Orange 16 (RO16) via photocatalysis involving TiO2/UV and TiO2/UV/oxidant systems has been investigated. The experiments were carried out in a stirred cylindrical batch photoreactor under UV irradiation. The effects of pH, TiO2 concentration and addition of electron acceptors such as H2O2, Na2S2O8 and Cu+ ions were studied. The decolourization efficiency followed the order of pH 3 > pH 9 > pH 6 in TiO2/UV system. The addition of Cu+ ions to TiO2/UV/oxidant system significantly increased the decolourization efficiency. The performance of addition of 0.5 mM Cu+ ions to TiO2/UV/Na2S2O8 system was also evaluated by using synthetic dye-bath effluent. The results reveal that almost complete decolourization (99%) was achieved with RO16, while 76% decolourization was obtained with synthetic dye-bath effluent after 360 min of reaction time. Similar trend was observed with COD measurements. The rate of decolourization of RO16 was found to follow pseudo-first order kinetics and obeys L-H model. When the suspension of TiO2 containing RO16 was exposed to solar irradiation, 90% of decolourization and 64% of COD removal were obtained after 120 min of reaction time. Degradation products of RO16 were determined by LCMS.