3-Oxetanone, also called oxetan-3-one or 1,3-epoxy-2-propanone, is a chemical compound with formula C3H4O2.

It is the ketone of oxetane, and an isomer of β-propiolactone.

3-Oxetanone is a liquid at room temperature, that boils at 140 °C.

It is a specialty chemical,[1][2] used for research in the synthesis of other oxetanes of pharmacological interest.

[3][4] Oxetan-3-one also has been the object of theoretical studies.