Oxygen demand is an environmental chemistry term that may refer to:
Biochemical oxygen demand (BOD), the amount of oxygen needed by organisms to break down organic material present in a water sample Carbonaceous biochemical oxygen demand (CBOD), the amount of oxygen needed to break down carbon compounds, excluding nitrogen compounds Chemical and biological oxygen demand, the combination of biochemical (BOD) and chemical oxygen demand (COD) Chemical oxygen demand (COD), a test commonly used to indirectly measure the amount of organic compounds in a water sample Nitrogenous oxygen demand (NOD), the amount of oxygen required to break down nitrogenous compounds in a water sample, like ammonia Theoretical oxygen demand (ThOD), the calculated amount of oxygen required to oxidize a compound to its final oxidation products