Graphene-TiO2, Photocatalytic degradation, Olive mill Wastewater, UV Irradiation Olive oil mill wastewater contains high concentration of organic matter, acidic pH values, suspended solids and high content of phenols and polyphenols which are toxic substances. In this study, Graphene-TiO2 was used to treat the pollutants from the olive mill industry wastewaters by photo-degradation. Graphene is an allotrope of carbon in the form of two-dimensional, atomic-scale, hexagonal lattices in which one atom form each vortex. It includes graphite, charcoal, carbon nanotubes and fullerenes. The large-scale production of functionalized graphene at low cost should result in good adsorbents for water purification. This is due to the two-dimensional layer structure, large surface area, pore volume and presence of surface functional groups in these materials; the inorganic nanoparticles also prevent aggregation of the adsorbent. XRD distribution peaks showed that GO existed in the XRD pattern which shows that a small quantity of GO and play a part in the intercalating process of TiO2-Graphene Oxide. SEM analysis results showed that the graphene oxide layers consist from the connection of the graphene oxide flakes during the reaction between C=O in the edge of graphene oxide. In this study the photo-removals of COD, total solid and total phenol in olive mill effluent wastewater with Graphene-TiO2 were investigated under photocatalytic oxidation. The effects of increasing Graphene-TiO2 concentrations (0.5 g/L, 1 g/L 3 g/L, 5 g/L and 10 g/L), photooxidation times (15, 30, 60 and 90 min) and pH (4, 7 and 10) were evaluated on the treatment of OMW pollutants. The photocatalytic reactions were performed under UV irradiation. The maximum pollutant removal efficiencies for COD, total phenol and TS obtained under 300 W UV light were 88%, 92% and 95% throughout photocatalysis at the optimum Graphene-TiO2 concentration (3 g/L). The maximum recovery capacity of Graphene-TiO2 was found between 90 and 95% after sequential six cycles.