Pesticides, hormones, pharmaceuticals, dyes, parasites, and heavy metals are common contaminants in aquatic environments; reaching the wastewater via domestic and industrial effluents affects human health. Heterogeneous photocatalysis techniques as an advanced oxidation process focus on removing these contaminants. On the other hand, recently, as the most abundant natural biopolymer globally, cellulose has attracted much attention. This review reviews recent research on the different applications of cellulose/TiO2 in wastewater treatment, starting with a brief introduction to the background of wastewater and the different processes of wastewater treatment, especially advanced oxidation processes. Then, general information of titanium, the structure of titanium oxide (TiO2), and TiO2 mechanism in water treatment followed by cellulose structure and its modified forms. In the end, different applications of cellulose/TiO2 in wastewater treatment are discussed. Also, the conclusion and future directions from my perspectives are given.