3-Oxetanone, also called oxetan-3-one or 1,3-epoxy-2-propanone, is a chemical compound with formula C<sub>3</sub>H<sub>4</sub>O<sub>2</sub>. It is the ketone of oxetane, and an isomer of ò-propiolactone.
3-Oxetanone is a liquid at room temperature, that boils at 140 ðC. It is a specialty chemical, used for research in the synthesis of other oxetanes of pharmacological interest. Oxetan-3-one also has been the object of theoretical studies.