In chemistry, an amine oxide, also known as an amine N-oxide or simply N-oxide, is a chemical compound that has the chemical formula . It contains a nitrogen-oxygen coordinate covalent bond with three additional hydrogen and/or substituent-groups attached to nitrogen. Sometimes it is written as  or, alternatively, as .
In the strict sense, the term amine oxide applies only to oxides of tertiary amines. Sometimes it is also used for the analogous derivatives of primary and secondary amines.
Examples of amine oxides include pyridine-N-oxide, a water-soluble crystalline solid with melting point 62–67 °C, and N-methylmorpholine N-oxide, which is an oxidant.